Pub Date : 2024-11-02DOI: 10.1016/j.jqsrt.2024.109251
Kailash, SS Verma
In this work, Mie theory is employed to study the opto-thermal response of magneto plasmonic Fe/Co/Ni@Au and Fe/Co/Ni@Ag core-shell nanostructures of different sizes in the presence of dielectric media (i.e., water) is investigated numerically. The optical and thermal characteristics from the Fe, Co, and Ni as core material with noble metal Au and Ag as coating (shell) material are susceptible to being well-tuned by controlling the dimensions of both core and shell, based on the research being conducted at the moment. The SPR wavelength spectra of magnetic core Fe /Co /Ni (radii ranging from 10–40 nm) with Au and Ag coating (fixed shell thickness of 5, 10, and 15 nm), nanostructures are tuned from 231–528 nm and 364–420 nm, respectively. The maximum temperature obtained near the surface of Fe/Co/Ni@Au and Fe/Co/Ni@Ag nanospheres with the optimized size is 2.09℃ / 2.09 ℃ / 2.23 ℃ and 2.30 ℃ / 2.33 ℃ / 2.33 ℃, respectively. It can be observed that the surface plasmon resonance (SPR) is located in the vicinity of the ultraviolet (UV) and infrared (IR) domains of the electromagnetic (EM) spectra. The temperature rise noticed in the nanoparticle (NP) has been attributed to enhanced absorbance efficiency.
{"title":"Size-dependent optical properties and thermal response of Fe/Co/Ni@Au and Fe/Co/Ni@Ag core-shell nanospheres","authors":"Kailash, SS Verma","doi":"10.1016/j.jqsrt.2024.109251","DOIUrl":"10.1016/j.jqsrt.2024.109251","url":null,"abstract":"<div><div>In this work, Mie theory is employed to study the opto-thermal response of magneto plasmonic Fe/Co/Ni@Au and Fe/Co/Ni@Ag core-shell nanostructures of different sizes in the presence of dielectric media (i.e., water) is investigated numerically. The optical and thermal characteristics from the Fe, Co, and Ni as core material with noble metal Au and Ag as coating (shell) material are susceptible to being well-tuned by controlling the dimensions of both core and shell, based on the research being conducted at the moment. The SPR wavelength spectra of magnetic core Fe /Co /Ni (radii ranging from 10–40 nm) with Au and Ag coating (fixed shell thickness of 5, 10, and 15 nm), nanostructures are tuned from 231–528 nm and 364–420 nm, respectively. The maximum temperature obtained near the surface of Fe/Co/Ni@Au and Fe/Co/Ni@Ag nanospheres with the optimized size is 2.09℃ / 2.09 ℃ / 2.23 ℃ and 2.30 ℃ / 2.33 ℃ / 2.33 ℃, respectively. It can be observed that the surface plasmon resonance (SPR) is located in the vicinity of the ultraviolet (UV) and infrared (IR) domains of the electromagnetic (EM) spectra. The temperature rise noticed in the nanoparticle (NP) has been attributed to enhanced absorbance efficiency.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109251"},"PeriodicalIF":2.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1016/j.jqsrt.2024.109225
Andrei Sokolov , Sergei N. Yurchenko , Jonathan Tennyson , Robert R. Gamache , Bastien Vispoel
A comprehensive semi-classical study of the collisional line broadening and shift coefficients of CH by several key perturbers (H, He, N, CH, CO, and CO2) for astronomical applications using the Complex Robert–Bonamy–Ma (CRBM) framework is presented. Following the CRBM computational protocol, the intermolecular interaction potentials are constructed from atom–atom and electrostatic interactions, and then fitted to reproduce experimental room-temperature line-broadening parameters taken from the literature. In total, 657 experimental values are used in the fitting. The empirical potentials are then used to predict line broadening coefficients over a wide temperature range. Reference collisional line widths and temperature exponents for the commonly used single-power law are produced, as well as a set of parameters for the double-power law, which better reproduces the temperature dependence of theoretical predictions. The vibrational dependence of the line widths is studied using a new ab initio isotropic polarizability surface of CH and is found to be negligible. The computed line broadening parameters are found to agree well with the experimental data, while the modelling of line shifts of HCCH is not satisfactory when compared to the experiment. The new line broadening data of CH with the (or ) dependence have been used to populate the ExoMol database www.exomol.com as part of the ExoMol pressure-broadening diet and can be used to model opacities of atmosphere of (extrasolar) planets. The CRBM methodology tested here on CH can be used for other similar (closed-shell) systems in ExoMol that are important for exoplanetary atmospheric studies.
{"title":"Calculation of collisional line-broadening and shifting of acetylene using Complex Robert–Bonamy–Ma approach","authors":"Andrei Sokolov , Sergei N. Yurchenko , Jonathan Tennyson , Robert R. Gamache , Bastien Vispoel","doi":"10.1016/j.jqsrt.2024.109225","DOIUrl":"10.1016/j.jqsrt.2024.109225","url":null,"abstract":"<div><div>A comprehensive semi-classical study of the collisional line broadening and shift coefficients of C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> by several key perturbers (H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, He, N<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, CO, and CO<sub>2</sub>) for astronomical applications using the Complex Robert–Bonamy–Ma (CRBM) framework is presented. Following the CRBM computational protocol, the intermolecular interaction potentials are constructed from atom–atom and electrostatic interactions, and then fitted to reproduce experimental room-temperature line-broadening parameters taken from the literature. In total, 657 experimental values are used in the fitting. The empirical potentials are then used to predict line broadening coefficients over a wide temperature range. Reference collisional line widths <span><math><msub><mrow><mi>γ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> and temperature exponents <span><math><mi>n</mi></math></span> for the commonly used single-power law are produced, as well as a set of parameters for the double-power law, which better reproduces the temperature dependence of theoretical predictions. The vibrational dependence of the line widths is studied using a new <em>ab initio</em> isotropic polarizability surface of C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and is found to be negligible. The computed line broadening parameters are found to agree well with the experimental data, while the modelling of line shifts of HCCH is not satisfactory when compared to the experiment. The new line broadening data of C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> with the <span><math><mi>J</mi></math></span> (or <span><math><mi>m</mi></math></span>) dependence have been used to populate the ExoMol database <span><span>www.exomol.com</span><svg><path></path></svg></span> as part of the ExoMol pressure-broadening diet and can be used to model opacities of atmosphere of (extrasolar) planets. The CRBM methodology tested here on C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> can be used for other similar (closed-shell) systems in ExoMol that are important for exoplanetary atmospheric studies.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109225"},"PeriodicalIF":2.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jqsrt.2024.109257
P.S. Puppi , A. Souza Barbosa , N.C. Jones , S.V. Hoffmann , U.S. Akther , N.J. Mason , P. Limão-Vieira
Synchrotron radiation has been used to record for the first time absolute vacuum ultraviolet photoabsorption cross-sections of trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA) in the 4.5–10.8 eV energy range. In order to further our knowledge of the major electronic transitions and thus help interpret the photoabsorption data, theoretical calculations using time-dependent density functional theory (TD-DFT) level have been performed. These calculations have provided important information on the nature of the excited electronic states which have been assigned to valence, mixed valence-Rydberg and Rydberg transitions. Due to the lack of any information about CDFA ionic states, we also provide Equation-of-Motion Coupled-Cluster Single and Doubles (EOM-CCSD) vertical ionisation energies. Photolysis lifetimes in the Earth's atmosphere for both chemical compounds have also been estimated from the absolute photoabsorption cross-section data.
利用同步辐射首次记录了三氟乙酸（TFA）和二氟氯乙酸（CDFA）在 4.5-10.8 eV 能量范围内的绝对真空紫外光吸收截面。为了进一步了解主要的电子跃迁，从而帮助解释光吸收数据，我们使用时间相关密度泛函理论（TD-DFT）水平进行了理论计算。这些计算提供了有关激发电子态性质的重要信息，这些电子态被归类为价态、价-雷伯格混合态和雷伯格跃迁态。由于缺乏有关 CDFA 离子状态的任何信息，我们还提供了运动方程耦合-簇单倍和双倍（EOM-CCSD）垂直电离能。我们还根据绝对光吸收截面数据估算了这两种化合物在地球大气中的光解寿命。
{"title":"The electronic spectra of trifluoroacetic acid and chlorodifluoroacetic acid in the 4.5 – 10.8 eV photon energy region","authors":"P.S. Puppi , A. Souza Barbosa , N.C. Jones , S.V. Hoffmann , U.S. Akther , N.J. Mason , P. Limão-Vieira","doi":"10.1016/j.jqsrt.2024.109257","DOIUrl":"10.1016/j.jqsrt.2024.109257","url":null,"abstract":"<div><div>Synchrotron radiation has been used to record for the first time absolute vacuum ultraviolet photoabsorption cross-sections of trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA) in the 4.5–10.8 eV energy range. In order to further our knowledge of the major electronic transitions and thus help interpret the photoabsorption data, theoretical calculations using time-dependent density functional theory (TD-DFT) level have been performed. These calculations have provided important information on the nature of the excited electronic states which have been assigned to valence, mixed valence-Rydberg and Rydberg transitions. Due to the lack of any information about CDFA ionic states, we also provide Equation-of-Motion Coupled-Cluster Single and Doubles (EOM-CCSD) vertical ionisation energies. Photolysis lifetimes in the Earth's atmosphere for both chemical compounds have also been estimated from the absolute photoabsorption cross-section data.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109257"},"PeriodicalIF":2.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jqsrt.2024.109244
Haifa Alali , Yong-Le Pan , Aimable Kalume , Yongxiang Hu , Yehor Surkov , Yuriy Shkuratov , Gorden Videen , Chuji Wang
The circular intensity differential scattering (CIDS), which is the normalized Mueller matrix element -S14/S11, has been measured from single biological particles as a function of scattering angle. CIDS is valuable for its potential in detecting chiral particles that may include the helical structures of DNA or RNA molecules in biological samples, and as such is a potential method for detecting biological particles. Optical trapping is employed to levitate single particles within a custom-designed elliptical reflector for CIDS measurements. The advantage of optical levitation in light-scattering measurements is that single particles can be suspended in air with sufficient working distance to prevent interference from the suspending apparatus. To measure the phase function, the reflector is used to collect the angle-dependent scattering signals. We demonstrated that we can obtain two-dimensional angular optical scattering (TAOS) patterns that cover a wide angular range from single levitated particles. These TAOS patterns are generated using 532 nm illumination of left-handed and right-handed circular polarizations and recorded from trapped single particles (silica, English Oak, Ragweed, Mulberry, Glycine, and l-Aspartic acid).
{"title":"Measurement of circular intensity differential scattering (CIDS) from single optically trapped biological particles","authors":"Haifa Alali , Yong-Le Pan , Aimable Kalume , Yongxiang Hu , Yehor Surkov , Yuriy Shkuratov , Gorden Videen , Chuji Wang","doi":"10.1016/j.jqsrt.2024.109244","DOIUrl":"10.1016/j.jqsrt.2024.109244","url":null,"abstract":"<div><div>The circular intensity differential scattering (CIDS), which is the normalized Mueller matrix element -S<sub>14</sub>/S<sub>11</sub>, has been measured from single biological particles as a function of scattering angle. CIDS is valuable for its potential in detecting chiral particles that may include the helical structures of DNA or RNA molecules in biological samples, and as such is a potential method for detecting biological particles. Optical trapping is employed to levitate single particles within a custom-designed elliptical reflector for CIDS measurements. The advantage of optical levitation in light-scattering measurements is that single particles can be suspended in air with sufficient working distance to prevent interference from the suspending apparatus. To measure the phase function, the reflector is used to collect the angle-dependent scattering signals. We demonstrated that we can obtain two-dimensional angular optical scattering (TAOS) patterns that cover a wide angular range from single levitated particles. These TAOS patterns are generated using 532 nm illumination of left-handed and right-handed circular polarizations and recorded from trapped single particles (silica, English Oak, Ragweed, Mulberry, Glycine, and <span>l</span>-Aspartic acid).</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109244"},"PeriodicalIF":2.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.jqsrt.2024.109233
Jia Wu , Baodong Gai , Shu Hu , Zihao Liu , Tao Li , Xianglong Cai , Ming Xu , Dongdong Xu , Shutong He , Yannan Tan , Jialiang Zhang , Jingwei Guo
Preparation of metastable Kr atoms in the 5s[3/2]2 level via laser-induced ionization has been achieved. The temporal evolution of the intensity of Kr atomic spectral lines at 760.15 nm, 811.29 nm, and 431.96 nm was used to elucidate the production mechanisms of metastable Kr atoms. These mechanisms primarily involve two processes: the “excitation + radiation” process, dominated by multiphoton excitation and initial plasma-induced electron impact excitation, and the “ion-electron recombination” process, governed by avalanche ionization. The decay time constants of Kr atomic spectral lines, corresponding to the “excitation + radiation” and “ion-electron recombination” processes respectively, were obtained experimentally under both strong and weak ionization conditions. The experiments revealed delay in preparations of metastable Kr atoms between these two processes. To reduce the loss of metastable Kr atoms and effectively utilize their peak concentration, we drew inspiration from metastable rare gas lasers and proposed the “cycling” idea to keep metastable Kr atoms produced by these two processes as synchronized as possible. We used 811.29 nm laser to excite metastable Kr atoms generated rapidly during the “excitation + radiation” stage to the 5p[5/2]3 level. The Kr atoms returned to the 5s[3/2]2 level through spontaneous radiation, merging with metastable Kr atoms that were slowly produced during the “ion-electron recombination” stage. We hope that the “cycling” idea can shorten the delay in preparations of metastable Kr atoms from both processes and enhance the peak concentration of metastable Kr atoms. However, the experimental results didn't meet expectations, as we observed a decrease in the 811.29 nm fluorescence after laser excitation, attributed to the accumulation of 5p[5/2]3 level Kr atoms. These atoms undergo energy pooling to populate the 4d’[3/2]1 and 5d[7/2]3 levels, followed by absorption of 811.29 nm laser energy leading to photoionization. Reducing the concentration of 5p[5/2]3 level Kr atoms helps mitigate the reionization issue.
{"title":"Mechanism of metastable krypton atom preparation via laser-induced ionization","authors":"Jia Wu , Baodong Gai , Shu Hu , Zihao Liu , Tao Li , Xianglong Cai , Ming Xu , Dongdong Xu , Shutong He , Yannan Tan , Jialiang Zhang , Jingwei Guo","doi":"10.1016/j.jqsrt.2024.109233","DOIUrl":"10.1016/j.jqsrt.2024.109233","url":null,"abstract":"<div><div>Preparation of metastable Kr atoms in the 5s[3/2]<sub>2</sub> level via laser-induced ionization has been achieved. The temporal evolution of the intensity of Kr atomic spectral lines at 760.15 nm, 811.29 nm, and 431.96 nm was used to elucidate the production mechanisms of metastable Kr atoms. These mechanisms primarily involve two processes: the “excitation + radiation” process, dominated by multiphoton excitation and initial plasma-induced electron impact excitation, and the “ion-electron recombination” process, governed by avalanche ionization. The decay time constants of Kr atomic spectral lines, corresponding to the “excitation + radiation” and “ion-electron recombination” processes respectively, were obtained experimentally under both strong and weak ionization conditions. The experiments revealed delay in preparations of metastable Kr atoms between these two processes. To reduce the loss of metastable Kr atoms and effectively utilize their peak concentration, we drew inspiration from metastable rare gas lasers and proposed the “cycling” idea to keep metastable Kr atoms produced by these two processes as synchronized as possible. We used 811.29 nm laser to excite metastable Kr atoms generated rapidly during the “excitation + radiation” stage to the 5p[5/2]<sub>3</sub> level. The Kr atoms returned to the 5s[3/2]<sub>2</sub> level through spontaneous radiation, merging with metastable Kr atoms that were slowly produced during the “ion-electron recombination” stage. We hope that the “cycling” idea can shorten the delay in preparations of metastable Kr atoms from both processes and enhance the peak concentration of metastable Kr atoms. However, the experimental results didn't meet expectations, as we observed a decrease in the 811.29 nm fluorescence after laser excitation, attributed to the accumulation of 5p[5/2]<sub>3</sub> level Kr atoms. These atoms undergo energy pooling to populate the 4d’[3/2]<sub>1</sub> and 5d[7/2]<sub>3</sub> levels, followed by absorption of 811.29 nm laser energy leading to photoionization. Reducing the concentration of 5p[5/2]<sub>3</sub> level Kr atoms helps mitigate the reionization issue.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109233"},"PeriodicalIF":2.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.jqsrt.2024.109229
Hongxu Li, Tao Ren, Changying Zhao
Hyperspectral absorption tomography has emerged as a promising technique for combustion diagnostics due to its rich spectral measurements. However, the non-linear and ill-posed nature of the inverse problem makes obtaining accurate results challenging. This paper proposes a novel application of a physics-informed neural network to address the non-linear inverse problem in hyperspectral absorption spectroscopy. This method utilizes physical laws and measurement data to guide the neural network in finding the optimal solution, without requiring training data. To demonstrate its capabilities, the physics-informed neural network is employed to retrieve temperature and CO mole fraction fields in axisymmetric laminar diffusion flames via TDLAS (tunable diode laser absorption spectroscopy). The developed neural network is applied to resolve the spatial distributions from the spectral dimensions, requiring fewer spatial measurements for directly retrieving temperature and CO mole fraction profiles. We investigate the minimum radial projections needed for accurate retrievals and evaluate the model’s robustness to random noise through the inversion of a simulated flame. The developed model is further applied to reconstruct the temperature and CO mole fraction fields for an experimentally measured flame. Our results demonstrate that the proposed model maintains high retrieval accuracy even with limited, noisy data. This work highlights the potential of the physics-informed neural network for robust solutions to non-linear laser absorption tomography problems in scientific and engineering applications.
{"title":"A physics-informed neural network for non-linear laser absorption tomography","authors":"Hongxu Li, Tao Ren, Changying Zhao","doi":"10.1016/j.jqsrt.2024.109229","DOIUrl":"10.1016/j.jqsrt.2024.109229","url":null,"abstract":"<div><div>Hyperspectral absorption tomography has emerged as a promising technique for combustion diagnostics due to its rich spectral measurements. However, the non-linear and ill-posed nature of the inverse problem makes obtaining accurate results challenging. This paper proposes a novel application of a physics-informed neural network to address the non-linear inverse problem in hyperspectral absorption spectroscopy. This method utilizes physical laws and measurement data to guide the neural network in finding the optimal solution, without requiring training data. To demonstrate its capabilities, the physics-informed neural network is employed to retrieve temperature and CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> mole fraction fields in axisymmetric laminar diffusion flames via <span><math><mrow><mn>4</mn><mo>.</mo><mn>3</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> TDLAS (tunable diode laser absorption spectroscopy). The developed neural network is applied to resolve the spatial distributions from the spectral dimensions, requiring fewer spatial measurements for directly retrieving temperature and CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> mole fraction profiles. We investigate the minimum radial projections needed for accurate retrievals and evaluate the model’s robustness to random noise through the inversion of a simulated flame. The developed model is further applied to reconstruct the temperature and CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> mole fraction fields for an experimentally measured flame. Our results demonstrate that the proposed model maintains high retrieval accuracy even with limited, noisy data. This work highlights the potential of the physics-informed neural network for robust solutions to non-linear laser absorption tomography problems in scientific and engineering applications.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109229"},"PeriodicalIF":2.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.jqsrt.2024.109243
Ihsan Farouki, Aamir Farooq, Bassam Dally
A mathematical method to enable absorption cross-section measurements using an optical cell with a non-uniform temperature distribution is formulated, validated and experimentally demonstrated in this study. The motivation of the proposed method is to facilitate high-temperature spectroscopic studies in the long-wavelength mid-IR region, and to offer an alternative to highly engineered optical cells. The method is based on virtual segmentation of the non-uniform temperature field within an optical cell into bins, each having a sufficiently uniform temperature. By collecting a set of absorbance measurements corresponding to unique temperature profiles and expressing the temperature dependence of the absorption cross-section in terms of a model with limited number of unknowns, a closed-form system of equations is obtained which can be solved to evaluate absorption cross-sections. It is shown, through a set of simulated validation cases, that modeling the temperature dependence in terms of a third order polynomial results in accurate reconstruction of the cross-section spectra for a wide range of cases. Piece-wise polynomials and an alternative nonlinear model are proposed for improved accuracy and to model potentially complex temperature dependencies of the absorption cross-sections. To demonstrate the application of the proposed method, an optical cell with a non-uniform temperature profile was used to measure the cross-section spectra of methane over 1280 – 1330 cm-1 at temperatures up to 523 K. The proposed method is expected to be highly useful in collecting spectroscopic data at high temperatures particularly in the mid-infrared region.
本研究提出了一种数学方法，可利用温度分布不均匀的光学池测量吸收截面，该方法经过验证和实验演示。提出该方法的动机是促进长波长中红外区域的高温光谱研究，并为高度工程化的光学池提供一种替代方法。该方法的基础是将光学池内的非均匀温度场虚拟分割成不同的区块，每个区块都有足够均匀的温度。通过收集一组与独特温度曲线相对应的吸光度测量值，并用一个未知数数量有限的模型来表示吸收截面的温度依赖性，就可以得到一个闭式方程组，通过求解该方程组就可以评估吸收截面。通过一组模拟验证案例表明，用三次多项式来表示温度依赖性模型，可以在多种情况下准确地重建横截面光谱。为了提高精确度，并对吸收截面潜在的复杂温度依赖性进行建模，提出了分段多项式和另一种非线性模型。为了演示所提方法的应用，我们使用了一个具有非均匀温度曲线的光学池来测量温度高达 523 K 的甲烷在 1280 - 1330 cm-1 范围内的横截面光谱。
{"title":"Measurement of high-temperature absorption cross-sections using an optical cell with a non-uniform temperature distribution","authors":"Ihsan Farouki, Aamir Farooq, Bassam Dally","doi":"10.1016/j.jqsrt.2024.109243","DOIUrl":"10.1016/j.jqsrt.2024.109243","url":null,"abstract":"<div><div>A mathematical method to enable absorption cross-section measurements using an optical cell with a non-uniform temperature distribution is formulated, validated and experimentally demonstrated in this study. The motivation of the proposed method is to facilitate high-temperature spectroscopic studies in the long-wavelength mid-IR region, and to offer an alternative to highly engineered optical cells. The method is based on virtual segmentation of the non-uniform temperature field within an optical cell into bins, each having a sufficiently uniform temperature. By collecting a set of absorbance measurements corresponding to unique temperature profiles and expressing the temperature dependence of the absorption cross-section in terms of a model with limited number of unknowns, a closed-form system of equations is obtained which can be solved to evaluate absorption cross-sections. It is shown, through a set of simulated validation cases, that modeling the temperature dependence in terms of a third order polynomial results in accurate reconstruction of the cross-section spectra for a wide range of cases. Piece-wise polynomials and an alternative nonlinear model are proposed for improved accuracy and to model potentially complex temperature dependencies of the absorption cross-sections. To demonstrate the application of the proposed method, an optical cell with a non-uniform temperature profile was used to measure the cross-section spectra of methane over 1280 – 1330 cm<sup>-1</sup> at temperatures up to 523 K. The proposed method is expected to be highly useful in collecting spectroscopic data at high temperatures particularly in the mid-infrared region.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109243"},"PeriodicalIF":2.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.jqsrt.2024.109255
Francesca Vitali , Stefania Stefani , Giuseppe Piccioni , Marcel Snels , Davide Grassi , David Biondi , Angelo Boccaccini
The Collision-Induced Absorption (CIA) fundamental band of H2 has been studied in the 3600–5500 cm−1 spectral range for temperatures ranging from 120 to 500 K for both a pure H2 gas and a H2-He mixture. We used a simulation chamber called PASSxS (Planetary Atmosphere System Simulation x Spectroscopy) developed at INAF/ISAC which contains a Multi-Pass cell interfaced with a Fourier Spectrometer, aligned to reach an optical path of 3.28 m. The H2-H2 and H2-He binary absorption coefficients (BACs) have been derived for seven temperatures in the chosen range and provided in tabular form, including the unexplored high-temperature range above 300 K. We also calculated the integral of the H2-H2 and H2-He experimental BACs in the reduced 4000–5000 cm−1 spectral range, finding a linear trend with temperature in both cases. The integrals have also been computed with larger uncertainties for the whole band, in the total 3600–5500 cm−1 spectral range including the band's wings, partially affected by the water vapor absorption. The integrals calculated over the whole and reduced spectral ranges are collected in tables. In addition, we performed measurements with a H2-He mix for different mixing ratios to explore possible deviations from the linear combination of the BACs. The experimental BACs have been shown in comparison with Abel and Borysow's ab initio models for a temperature of about 400 K, resulting in a good agreement over almost the whole spectral range, with a maximum deviation around the main peak of the band. Data and models also show a good agreement in the linear trend of the integrated BACs with temperature, apart from the H2-H2 Borysow's BACs, which follow a quadratic trend. Finally, we resolved all the interference dips, which were not taken into account by the existing theoretical models.
{"title":"New experimental measurements of the Collision Induced Absorptions of H2-H2 and H2-He in the 3600-5500 cm−1 spectral range from 120 to 500 K","authors":"Francesca Vitali , Stefania Stefani , Giuseppe Piccioni , Marcel Snels , Davide Grassi , David Biondi , Angelo Boccaccini","doi":"10.1016/j.jqsrt.2024.109255","DOIUrl":"10.1016/j.jqsrt.2024.109255","url":null,"abstract":"<div><div>The Collision-Induced Absorption (CIA) fundamental band of H<sub>2</sub> has been studied in the 3600–5500 cm<sup>−1</sup> spectral range for temperatures ranging from 120 to 500 K for both a pure H<sub>2</sub> gas and a H<sub>2</sub>-He mixture. We used a simulation chamber called PASSxS (Planetary Atmosphere System Simulation x Spectroscopy) developed at INAF/ISAC which contains a Multi-Pass cell interfaced with a Fourier Spectrometer, aligned to reach an optical path of 3.28 m. The H<sub>2</sub>-H<sub>2</sub> and H<sub>2</sub>-He binary absorption coefficients (BACs) have been derived for seven temperatures in the chosen range and provided in tabular form, including the unexplored high-temperature range above 300 K. We also calculated the integral of the H<sub>2</sub>-H<sub>2</sub> and H<sub>2</sub>-He experimental BACs in the reduced 4000–5000 cm<sup>−1</sup> spectral range, finding a linear trend with temperature in both cases. The integrals have also been computed with larger uncertainties for the whole band, in the total 3600–5500 cm<sup>−1</sup> spectral range including the band's wings, partially affected by the water vapor absorption. The integrals calculated over the whole and reduced spectral ranges are collected in tables. In addition, we performed measurements with a H<sub>2</sub>-He mix for different mixing ratios to explore possible deviations from the linear combination of the BACs. The experimental BACs have been shown in comparison with Abel and Borysow's <em>ab initio</em> models for a temperature of about 400 K, resulting in a good agreement over almost the whole spectral range, with a maximum deviation around the main peak of the band. Data and models also show a good agreement in the linear trend of the integrated BACs with temperature, apart from the H<sub>2</sub>-H<sub>2</sub> Borysow's BACs, which follow a quadratic trend. Finally, we resolved all the interference dips, which were not taken into account by the existing theoretical models.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109255"},"PeriodicalIF":2.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.jqsrt.2024.109234
Mofreh R. Zaghloul , Jacques Le Bourlot
Evaluation of the Voigt function, a convolution of a Lorentzian and a Gaussian profile, is essential in various fields such as spectroscopy, atmospheric science, and astrophysics. Efficient computation of the function is crucial, especially in applications where the function may be called for an enormous number of times. In this paper, we present a highly efficient novel algorithm and its Fortran90 implementation for the practical evaluation of the Voigt function with accuracy in the order of . The algorithm uses improved fits based on Chebyshev subinterval polynomial approximation for functions in two variables. The algorithm significantly outperforms widely-used competitive algorithms in the literature, in terms of computational speed, making it highly suitable for real-time applications and large-scale data processing tasks. The substantial improvement in efficiency positions the present algorithm and computer code as a valuable tool in relevant scientific domains. The algorithm has been adopted and implemented in the Meudon PDR code at Paris Observatory and is recommended for similar applications and simulation packages.
{"title":"A highly efficient Voigt program for line profile computation","authors":"Mofreh R. Zaghloul , Jacques Le Bourlot","doi":"10.1016/j.jqsrt.2024.109234","DOIUrl":"10.1016/j.jqsrt.2024.109234","url":null,"abstract":"<div><div>Evaluation of the Voigt function, a convolution of a Lorentzian and a Gaussian profile, is essential in various fields such as spectroscopy, atmospheric science, and astrophysics. Efficient computation of the function is crucial, especially in applications where the function may be called for an enormous number of times. In this paper, we present a highly efficient novel algorithm and its Fortran90 implementation for the practical evaluation of the Voigt function with accuracy in the order of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></math></span>. The algorithm uses improved fits based on Chebyshev subinterval polynomial approximation for functions in two variables. The algorithm significantly outperforms widely-used competitive algorithms in the literature, in terms of computational speed, making it highly suitable for real-time applications and large-scale data processing tasks. The substantial improvement in efficiency positions the present algorithm and computer code as a valuable tool in relevant scientific domains. The algorithm has been adopted and implemented in the Meudon PDR code at Paris Observatory and is recommended for similar applications and simulation packages.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109234"},"PeriodicalIF":2.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.jqsrt.2024.109226
Karri Muinonen , Ari Leppälä , Johannes Markkanen
We consider radiative transfer and coherent backscattering (RT-CB) in a discrete random medium of particles. The elementary scattering matrix of the medium conforms to the ensemble-averaged scattering matrix for nonspherical particles and their mirror particles, both in random orientation. We express the ensemble-averaged matrix, via spectral decomposition, as a linear superposition of four pure Mueller matrices, and enable RT-CB computations via an independent treatment of the pure matrices. We validate the method for sparsely and densely packed random media of spherical particles. For the case of sparse packing, we compare two different RT-CB approaches, one with explicit input of polydisperse spherical-particle characteristics and the other with input by decomposing the ensemble-averaged scattering matrix. The results are in agreement and reproduce markedly well the asymptotically exact results from the Fast Superposition -Matrix Method (FaSTMM). For the cases of dense packing, we compare the RT-CB to the FaSTMM by invoking the ensemble-averaged incoherent scattering matrix of volume elements as input for the RT-CB. For non-absorbing particles, the RT-CB agrees well with the FaSTMM. For strongly absorbing particles, there are deviations that underscore the need for further method development. In order to demonstrate the potential of the RT-CB, we compute multiple scattering for a sparsely packed spherical medium of nonspherical feldspar particles by utilizing their experimentally measured ensemble-averaged scattering phase matrix. Finally, we discuss future prospects for the RT-CB.
{"title":"Coherent backscattering in discrete random media of particle ensembles","authors":"Karri Muinonen , Ari Leppälä , Johannes Markkanen","doi":"10.1016/j.jqsrt.2024.109226","DOIUrl":"10.1016/j.jqsrt.2024.109226","url":null,"abstract":"<div><div>We consider radiative transfer and coherent backscattering (RT-CB) in a discrete random medium of particles. The elementary scattering matrix of the medium conforms to the ensemble-averaged scattering matrix for nonspherical particles and their mirror particles, both in random orientation. We express the ensemble-averaged matrix, via spectral decomposition, as a linear superposition of four pure Mueller matrices, and enable RT-CB computations via an independent treatment of the pure matrices. We validate the method for sparsely and densely packed random media of spherical particles. For the case of sparse packing, we compare two different RT-CB approaches, one with explicit input of polydisperse spherical-particle characteristics and the other with input by decomposing the ensemble-averaged scattering matrix. The results are in agreement and reproduce markedly well the asymptotically exact results from the Fast Superposition <span><math><mi>T</mi></math></span>-Matrix Method (FaSTMM). For the cases of dense packing, we compare the RT-CB to the FaSTMM by invoking the ensemble-averaged incoherent scattering matrix of volume elements as input for the RT-CB. For non-absorbing particles, the RT-CB agrees well with the FaSTMM. For strongly absorbing particles, there are deviations that underscore the need for further method development. In order to demonstrate the potential of the RT-CB, we compute multiple scattering for a sparsely packed spherical medium of nonspherical feldspar particles by utilizing their experimentally measured ensemble-averaged scattering phase matrix. Finally, we discuss future prospects for the RT-CB.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109226"},"PeriodicalIF":2.3,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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