Pub Date : 2024-10-23DOI: 10.1016/j.jqsrt.2024.109227
Matt Majic, Eric C. Le Ru
The T-matrix for electromagnetic scattering is most commonly computed using the Extended Boundary Condition Method (EBCM), but this approach is numerically unstable for finite cylinders of high aspect ratio. In the electrostatics limit, we show that this instability is caused by catastrophic cancellations in the numerical calculations of oscillatory integrals. We find that the problematic integrals can instead be evaluated by integrating over the complement surface that extends from the cylinder to infinity. The resulting integrals are stable and we are then able to compute the electrostatic T-matrix accurately. The polarizability of the finite cylinder is then derived from this T-matrix and validated against results obtained via discretization. As an alternative, we also investigate the T-matrix on a basis of spheroidal harmonics, which is stable on its own and converges more quickly than on the spherical basis. Since the integrals are analytic, we moreover derive a simple analytic approximation based on truncation of the T-matrix on this basis. Beyond the direct benefits of analytic expressions for the electrostatic cylinder polarizability, this work should pave the way for a stable formulation of the full-wave T-matrix/EBCM approach for cylinders.
电磁散射的 T 矩阵最常用扩展边界条件法（EBCM）来计算，但这种方法对于高纵横比的有限圆柱体在数值上是不稳定的。在静电极限中，我们证明这种不稳定性是由振荡积分数值计算中的灾难性抵消引起的。我们发现，可以通过对从圆柱体延伸到无穷远的补余面进行积分来计算有问题的积分。由此得到的积分是稳定的，这样我们就能精确计算静电 T 矩阵。有限圆柱体的极化性就是根据这个 T 矩阵推导出来的，并与离散化得到的结果进行了验证。作为替代方案，我们还在球面谐波的基础上研究了 T 矩阵，它本身是稳定的，而且比球面基础收敛得更快。由于积分是解析的，我们还根据在此基础上对 T 矩阵的截断推导出一个简单的解析近似值。除了静电圆柱体极化率解析表达式的直接益处之外，这项工作还将为圆柱体全波 T 矩阵/EBCM 方法的稳定表述铺平道路。
{"title":"Analytic results for the electrostatic T-matrix and polarizability of finite cylinders","authors":"Matt Majic, Eric C. Le Ru","doi":"10.1016/j.jqsrt.2024.109227","DOIUrl":"10.1016/j.jqsrt.2024.109227","url":null,"abstract":"<div><div>The T-matrix for electromagnetic scattering is most commonly computed using the Extended Boundary Condition Method (EBCM), but this approach is numerically unstable for finite cylinders of high aspect ratio. In the electrostatics limit, we show that this instability is caused by catastrophic cancellations in the numerical calculations of oscillatory integrals. We find that the problematic integrals can instead be evaluated by integrating over the complement surface that extends from the cylinder to infinity. The resulting integrals are stable and we are then able to compute the electrostatic T-matrix accurately. The polarizability of the finite cylinder is then derived from this T-matrix and validated against results obtained via discretization. As an alternative, we also investigate the T-matrix on a basis of spheroidal harmonics, which is stable on its own and converges more quickly than on the spherical basis. Since the integrals are analytic, we moreover derive a simple analytic approximation based on truncation of the T-matrix on this basis. Beyond the direct benefits of analytic expressions for the electrostatic cylinder polarizability, this work should pave the way for a stable formulation of the full-wave T-matrix/EBCM approach for cylinders.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109227"},"PeriodicalIF":2.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552240","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 : 2024-10-23DOI: 10.1016/j.jqsrt.2024.109228
Zhan-Bin Chen
This manuscript investigates the electronic structures, spectral properties, and photoionization processes of the confined atomic system. For this purpose, a relativistic methodology employing the Dirac–Coulomb Hamiltonian within the context of relativistic configuration interaction is suggested, utilizing independent particle basis wavefunctions. The key idea of this approach is to place the atom inside a Gaussian potential, which gives a realistic description of the spatial confinement in quantum dots due to a smooth change at the quantum dot boundaries and has a finite range and depth for the spatial confinement. As a result, the local central potential is modified, which is determined by a self-consistent process. The solutions to the Dirac equation, incorporating the aforementioned central potential, yield both the continuous and bound state wave functions. The photoionization process is determined through the application of the distorted wave approach within the context of relativistic Dirac theory. As an application, the electronic structures of the confined Li atom, including energies, ionization potentials, transition rates, and photoionization dynamical properties such as wave functions, cross sections, and photoelectron angular distributions, are systematically investigated within the dipole approximation for a wide range of potential depths and confining radii. A systematic comparison of the present outcomes is made with other available results. The present study is not only meaningful for fundamental research in atomic and molecular physics, but also has implications for a range of disciplines, such as nanochemistry, materials science, and other related fields.
{"title":"A theoretical exploration of the electronic structure and single photoionization of the many-electron system confined in Gaussian potential","authors":"Zhan-Bin Chen","doi":"10.1016/j.jqsrt.2024.109228","DOIUrl":"10.1016/j.jqsrt.2024.109228","url":null,"abstract":"<div><div>This manuscript investigates the electronic structures, spectral properties, and photoionization processes of the confined atomic system. For this purpose, a relativistic methodology employing the Dirac–Coulomb Hamiltonian within the context of relativistic configuration interaction is suggested, utilizing independent particle basis wavefunctions. The key idea of this approach is to place the atom inside a Gaussian potential, which gives a realistic description of the spatial confinement in quantum dots due to a smooth change at the quantum dot boundaries and has a finite range and depth for the spatial confinement. As a result, the local central potential is modified, which is determined by a self-consistent process. The solutions to the Dirac equation, incorporating the aforementioned central potential, yield both the continuous and bound state wave functions. The photoionization process is determined through the application of the distorted wave approach within the context of relativistic Dirac theory. As an application, the electronic structures of the confined Li atom, including energies, ionization potentials, transition rates, and photoionization dynamical properties such as wave functions, cross sections, and photoelectron angular distributions, are systematically investigated within the dipole approximation for a wide range of potential depths and confining radii. A systematic comparison of the present outcomes is made with other available results. The present study is not only meaningful for fundamental research in atomic and molecular physics, but also has implications for a range of disciplines, such as nanochemistry, materials science, and other related fields.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109228"},"PeriodicalIF":2.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527343","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 : 2024-10-21DOI: 10.1016/j.jqsrt.2024.109223
Johannes Lill , Andreas Dreizler , Gaetano Magnotti , Dirk Geyer
This paper presents a comprehensive simulation approach for the temperature-dependent Raman spectra of CO2, a common product in combustion and reactive environments. Previous studies have typically been limited to isotropic scattering or a restricted number of energy levels. In contrast, our simulation incorporates both isotropic and anisotropic scattering, including all ro-vibrational O, P, Q, R, and S transitions, and extends to all energy levels contained in and up to polyad 30, which our results demonstrate is essential for accurate modeling at high temperatures. The four most prevalent isotopologues , , , and are included, collectively accounting for over 99.99 % of naturally occurring CO2. Polarizability ratios between the and modes and the isotropic/anisotropic contributions were determined by fitting them to experimental spectra at 296 K. The simulated CO2 spectra demonstrate excellent agreement with experimental data across temperatures up to 2355 K, thereby enhancing the reliability of Raman spectroscopy in various applications involving CO2.
二氧化碳是燃烧和反应环境中的常见产物，本文针对二氧化碳随温度变化的拉曼光谱提出了一种综合模拟方法。以往的研究通常局限于各向同性散射或有限数量的能级。相比之下，我们的模拟结合了各向同性和各向异性散射，包括所有 O、P、Q、R 和 S 振荡跃迁，并扩展到多聚体 30 及以下的所有能级，我们的结果表明这对高温下的精确建模至关重要。四种最普遍的同素异形体、、、和都包括在内，共占天然存在的二氧化碳的 99.99% 以上。通过拟合 296 K 的实验光谱，确定了 v1 和 2v2 模式之间的极化率以及各向同性/各向异性贡献。模拟的二氧化碳光谱与高达 2355 K 的实验数据非常吻合，从而提高了拉曼光谱在涉及二氧化碳的各种应用中的可靠性。
{"title":"Accurate simulation of spontaneous Raman scattering of CO2 for high-temperature diagnostics","authors":"Johannes Lill , Andreas Dreizler , Gaetano Magnotti , Dirk Geyer","doi":"10.1016/j.jqsrt.2024.109223","DOIUrl":"10.1016/j.jqsrt.2024.109223","url":null,"abstract":"<div><div>This paper presents a comprehensive simulation approach for the temperature-dependent Raman spectra of CO<sub>2</sub>, a common product in combustion and reactive environments. Previous studies have typically been limited to isotropic scattering or a restricted number of energy levels. In contrast, our simulation incorporates both isotropic and anisotropic scattering, including all ro-vibrational O, P, Q, R, and S transitions, and extends to all energy levels contained in and up to polyad 30, which our results demonstrate is essential for accurate modeling at high temperatures. The four most prevalent isotopologues <figure><img></figure> , <figure><img></figure> , <figure><img></figure> , and <figure><img></figure> are included, collectively accounting for over 99.99 % of naturally occurring CO<sub>2</sub>. Polarizability ratios between the <span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><mrow><mn>2</mn><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span> modes and the isotropic/anisotropic contributions were determined by fitting them to experimental spectra at 296<!--> <!-->K. The simulated CO<sub>2</sub> spectra demonstrate excellent agreement with experimental data across temperatures up to 2355<!--> <!-->K, thereby enhancing the reliability of Raman spectroscopy in various applications involving CO<sub>2</sub>.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109223"},"PeriodicalIF":2.3,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527341","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 : 2024-10-20DOI: 10.1016/j.jqsrt.2024.109199
Song Ye , Baijun Dong , Wei Xiong , Ziyang Zhang , Shu Li , Xingqiang Wang , Fangyuan Wang , Wei Luo , Li Ma , Niyan Chen
The "GF Special Project" is a massive remote sensing technology initiative including a number of satellites and various observation platforms. GF-5 is the satellite with the most payloads, the highest spectral resolution, and the most difficulty in development, and it can monitor a variety of environmental elements using spatial heterodyne spectroscopy (SHS) technology, including atmospheric aerosols, carbon dioxide, methane, terrestrial vegetation, straw burning, and urban heat islands. In this study, a novel blind element error correction technique based on deep learning network is investigated and developed for spatial heterodyne interferograms, as well as the formation mechanism and distribution characteristics of the SHS interferometric data. LSConv-Net, a new CNN model, was created and trained to denoise in the presence of high-density and ultra-high-density blind element errors. We do this by introducing a new line-selective convolutional (LSConv) block. Simultaneously, experimental validation of blind element error correction utilizing laboratory water vapor interferometric data and atmospheric CO2 absorption interferometric data from GF-5, and the change in FWHM before and after the experiment was tested using potassium lamp interferograms. Experiments show that the Deep neural networks trained with this model may successfully suppress the effect of blind element noise on spectra, recover spectra that have been overwhelmed by high-density blind element noise without any effect on other non-blind pixels, and surpass all similar techniques in terms of spectral recovery.
{"title":"A deep convolutional neural network for blind element error correction of spatial heterodyne spectrometer using line selective convolutional blocks","authors":"Song Ye , Baijun Dong , Wei Xiong , Ziyang Zhang , Shu Li , Xingqiang Wang , Fangyuan Wang , Wei Luo , Li Ma , Niyan Chen","doi":"10.1016/j.jqsrt.2024.109199","DOIUrl":"10.1016/j.jqsrt.2024.109199","url":null,"abstract":"<div><div>The \"GF Special Project\" is a massive remote sensing technology initiative including a number of satellites and various observation platforms. GF-5 is the satellite with the most payloads, the highest spectral resolution, and the most difficulty in development, and it can monitor a variety of environmental elements using spatial heterodyne spectroscopy (SHS) technology, including atmospheric aerosols, carbon dioxide, methane, terrestrial vegetation, straw burning, and urban heat islands. In this study, a novel blind element error correction technique based on deep learning network is investigated and developed for spatial heterodyne interferograms, as well as the formation mechanism and distribution characteristics of the SHS interferometric data. LSConv-Net, a new CNN model, was created and trained to denoise in the presence of high-density and ultra-high-density blind element errors. We do this by introducing a new line-selective convolutional (LSConv) block. Simultaneously, experimental validation of blind element error correction utilizing laboratory water vapor interferometric data and atmospheric CO<sub>2</sub> absorption interferometric data from GF-5, and the change in FWHM before and after the experiment was tested using potassium lamp interferograms. Experiments show that the Deep neural networks trained with this model may successfully suppress the effect of blind element noise on spectra, recover spectra that have been overwhelmed by high-density blind element noise without any effect on other non-blind pixels, and surpass all similar techniques in terms of spectral recovery.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109199"},"PeriodicalIF":2.3,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593972","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 : 2024-10-18DOI: 10.1016/j.jqsrt.2024.109221
Marie Meulemans , Antoine Durocher , Philippe Versailles , Gilles Bourque , Jeffrey M. Bergthorson
Laser-Induced Fluorescence (LIF) is an essential optical diagnostic technique for the high-resolution and low-uncertainty measurement of combustion species concentration in a variety of applications and conditions. Two different calibration techniques are explored in this study to obtain quantitative Nitric Oxide (NO) concentration measurements in flames. The first technique, the most employed in the literature, uses the extrapolation of the fluorescence signal from seeded to nascent NO and is only valid under negligible NO reburn conditions. The second technique uses the optical calibration of the experimental setup to relate it to a modelled LIF signal and can be applied regardless of NO reburn. Both of these techniques are explored under two different assumptions: constant and non-constant interfering LIF signal on the NO absorption spectrum. While the former is most often used in the literature, the latter is necessary when the LIF signal from interfering species cannot be distinguished from the NO-LIF signal, especially in high pressure conditions. Hence, a total of four techniques are presented in this work and are found to be in excellent agreement when performed in different flame conditions. The calibration techniques are applied to three lean, atmospheric, laminar, premixed, methane-air flames to explore their field of applicability. Specifically, the study explores the relevance of the techniques in reburn conditions, which occur mostly in high pressure, rich, highly-seeded, or NH-containing flames. This study aims to offer the reader a portfolio of calibration techniques to use according to the conditions in which they need to be applied. While this study was carried out measuring NO concentration in a stagnation flame burner, the concepts and equations presented can be transposed to the measurement of other species and to other experimental configurations.
{"title":"Calibration techniques for quantitative NO measurement using Laser-Induced Fluorescence","authors":"Marie Meulemans , Antoine Durocher , Philippe Versailles , Gilles Bourque , Jeffrey M. Bergthorson","doi":"10.1016/j.jqsrt.2024.109221","DOIUrl":"10.1016/j.jqsrt.2024.109221","url":null,"abstract":"<div><div>Laser-Induced Fluorescence (LIF) is an essential optical diagnostic technique for the high-resolution and low-uncertainty measurement of combustion species concentration in a variety of applications and conditions. Two different calibration techniques are explored in this study to obtain quantitative Nitric Oxide (NO) concentration measurements in flames. The first technique, the most employed in the literature, uses the extrapolation of the fluorescence signal from seeded to nascent NO and is only valid under negligible NO reburn conditions. The second technique uses the optical calibration of the experimental setup to relate it to a modelled LIF signal and can be applied regardless of NO reburn. Both of these techniques are explored under two different assumptions: constant and non-constant interfering LIF signal on the NO absorption spectrum. While the former is most often used in the literature, the latter is necessary when the LIF signal from interfering species cannot be distinguished from the NO-LIF signal, especially in high pressure conditions. Hence, a total of four techniques are presented in this work and are found to be in excellent agreement when performed in different flame conditions. The calibration techniques are applied to three lean, atmospheric, laminar, premixed, methane-air flames to explore their field of applicability. Specifically, the study explores the relevance of the techniques in reburn conditions, which occur mostly in high pressure, rich, highly-seeded, or NH<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>-containing flames. This study aims to offer the reader a portfolio of calibration techniques to use according to the conditions in which they need to be applied. While this study was carried out measuring NO concentration in a stagnation flame burner, the concepts and equations presented can be transposed to the measurement of other species and to other experimental configurations.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109221"},"PeriodicalIF":2.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552239","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}
Understanding the radiative properties of particles is essential for interpreting and analyzing atmospheric remote sensing, target detection, combustion diagnostics, etc. At present, there is a relative lack of studies and understanding of the radiative properties of large aggregate particles. In this work, we comprehensively investigate the radiative properties of large dust aggregate particles via the developed Monte Carlo ray tracing method. Large dust aggregate models with monodisperse and polydisperse monomers are constructed, respectively. The effects of various factors on the radiative properties of large dust aggregate particles are analyzed. We find that the larger geometric standard deviation and the greater number of monomers lead to slightly larger backscattering and an increase of the overall radiative energy distribution on the receiving surface. With increasing the size parameter, the scattering phase function becomes smoother and the difference between the scattering phase function of spheres and aggregates diminishes. The absorptivity is proportional to the size parameter and inversely proportional to the number of monomers. At a size parameter of 100, the absorptivity and the peak of the radiative energy distribution of monodisperse monomer aggregates are higher than those of polydisperse monomer aggregates, and gradually converge with the increase of particle size parameter. Overall, this work helps to enhance the knowledge of the radiative properties of large aggregate particles.
{"title":"Investigating the radiative properties of large dust aggregate particles via the Monte Carlo ray tracing method","authors":"Xiaochuan Liu, Yanxia Tang, Keyong Zhu, Yong Huang","doi":"10.1016/j.jqsrt.2024.109219","DOIUrl":"10.1016/j.jqsrt.2024.109219","url":null,"abstract":"<div><div>Understanding the radiative properties of particles is essential for interpreting and analyzing atmospheric remote sensing, target detection, combustion diagnostics, etc. At present, there is a relative lack of studies and understanding of the radiative properties of large aggregate particles. In this work, we comprehensively investigate the radiative properties of large dust aggregate particles via the developed Monte Carlo ray tracing method. Large dust aggregate models with monodisperse and polydisperse monomers are constructed, respectively. The effects of various factors on the radiative properties of large dust aggregate particles are analyzed. We find that the larger geometric standard deviation and the greater number of monomers lead to slightly larger backscattering and an increase of the overall radiative energy distribution on the receiving surface. With increasing the size parameter, the scattering phase function becomes smoother and the difference between the scattering phase function of spheres and aggregates diminishes. The absorptivity is proportional to the size parameter and inversely proportional to the number of monomers. At a size parameter of 100, the absorptivity and the peak of the radiative energy distribution of monodisperse monomer aggregates are higher than those of polydisperse monomer aggregates, and gradually converge with the increase of particle size parameter. Overall, this work helps to enhance the knowledge of the radiative properties of large aggregate particles.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109219"},"PeriodicalIF":2.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527529","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 : 2024-10-18DOI: 10.1016/j.jqsrt.2024.109224
A. Kynienė, Š. Masys, V. Jonauskas
Ionization cross sections are studied for energy levels of the ground configurations of the Ne and Ne ions. The distorted wave (DW) approximation is used to analyze experimental data. The scaled DW cross sections are used to explain measurements for the Ne ion. Study includes analysis of contributions from the direct and indirect ionization processes. Convergences of excitation-autoionization (EA) channels are estimated by analyzing excitations up to shells with the principal quantum number . This study shows that the EA process provides from 10% to 20% for the energy levels of the ground configurations of the Ne and Ne ions.
{"title":"Electron-impact ionization for Ne3+ and Ne4+","authors":"A. Kynienė, Š. Masys, V. Jonauskas","doi":"10.1016/j.jqsrt.2024.109224","DOIUrl":"10.1016/j.jqsrt.2024.109224","url":null,"abstract":"<div><div>Ionization cross sections are studied for energy levels of the ground configurations of the Ne<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> and Ne<span><math><msup><mrow></mrow><mrow><mn>4</mn><mo>+</mo></mrow></msup></math></span> ions. The distorted wave (DW) approximation is used to analyze experimental data. The scaled DW cross sections are used to explain measurements for the Ne<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> ion. Study includes analysis of contributions from the direct and indirect ionization processes. Convergences of excitation-autoionization (EA) channels are estimated by analyzing excitations up to shells with the principal quantum number <span><math><mrow><mi>n</mi><mo>⩽</mo><mn>20</mn></mrow></math></span>. This study shows that the EA process provides from <span><math><mo>∼</mo></math></span>10% to 20% for the energy levels of the ground configurations of the Ne<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> and Ne<span><math><msup><mrow></mrow><mrow><mn>4</mn><mo>+</mo></mrow></msup></math></span> ions.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109224"},"PeriodicalIF":2.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527342","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 : 2024-10-18DOI: 10.1016/j.jqsrt.2024.109222
Aurélien Favre, Arnaud Bultel, Vincent Morel, Morgan Lesage, Léo Gosse
Optical Emission Spectroscopy is used within the LIBS (Laser-Induced Breakdown Spectroscopy) technique to measure the elemental composition of a sample irradiated by a laser pulse. When the objective is to characterize a known alloy or to analyze the sample semi-quantitatively, standards can be used. This method refers to the “calibrated LIBS”. When the studied sample is complex (for instance unknown alloy and/or concentration gradients), the modeling of the experimental emission spectra leads to the determination of the laser-induced plasma characteristics including its composition. This second method refers to the “calibration-free LIBS”.
In this paper, we present the radiative transfer code MERLIN (MultiElemental Radiative equiLibrIum emissioN) aiming at matching experimental spectra of a laser-induced plasma in Local Thermodynamic Equilibrium (LTE) conditions for calibration-free LIBS. MERLIN provides the simulated spectra for any elementary mixture thanks to queries from spectral databases available online. The code is optimized and modular to allow outputs even for a high number of species.
The validation of MERLIN presented in the paper is based on a thorough analysis of the plasma emission performed on the alloy Eurofer97 in experimental conditions providing the LTE. The reconstruction of the observed spectra is performed with MERLIN. For the reconstruction, no adjusted variable is required since all the necessary parameters are derived from experiments.
{"title":"MERLIN, an adaptative LTE radiative transfer model for any mixture: Validation on Eurofer97 in argon atmosphere","authors":"Aurélien Favre, Arnaud Bultel, Vincent Morel, Morgan Lesage, Léo Gosse","doi":"10.1016/j.jqsrt.2024.109222","DOIUrl":"10.1016/j.jqsrt.2024.109222","url":null,"abstract":"<div><div>Optical Emission Spectroscopy is used within the LIBS (Laser-Induced Breakdown Spectroscopy) technique to measure the elemental composition of a sample irradiated by a laser pulse. When the objective is to characterize a known alloy or to analyze the sample semi-quantitatively, standards can be used. This method refers to the “calibrated LIBS”. When the studied sample is complex (for instance unknown alloy and/or concentration gradients), the modeling of the experimental emission spectra leads to the determination of the laser-induced plasma characteristics including its composition. This second method refers to the “calibration-free LIBS”.</div><div>In this paper, we present the radiative transfer code MERLIN (MultiElemental Radiative equiLibrIum emissioN) aiming at matching experimental spectra of a laser-induced plasma in Local Thermodynamic Equilibrium (LTE) conditions for calibration-free LIBS. MERLIN provides the simulated spectra for any elementary mixture thanks to queries from spectral databases available online. The code is optimized and modular to allow outputs even for a high number of species.</div><div>The validation of MERLIN presented in the paper is based on a thorough analysis of the plasma emission performed on the alloy Eurofer97 in experimental conditions providing the LTE. The reconstruction of the observed spectra is performed with MERLIN. For the reconstruction, no adjusted variable is required since all the necessary parameters are derived from experiments.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109222"},"PeriodicalIF":2.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527528","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 : 2024-10-16DOI: 10.1016/j.jqsrt.2024.109218
R. Dodangodage , P.F. Bernath , C. Boone , J.J. Harrison , M. Lecours , M. Schmidt , S.A. Montzka , I. Vimont , M. Crotwell
HFC-125 (CFCHF, pentafluoroethane) volume mixing ratios (VMRs) have been determined for the first time using infrared absorption spectra from the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) from 2004 to 2024. These VMRs provide global altitude-latitude VMR distributions. A VMR time series for HFC-125 has also been calculated and compared to values from in situ discrete flask measurements conducted by the National Oceanic and Atmospheric Administration Earth System Research Laboratory. The abundance of HFC-125 is currently experiencing exponential growth. ACE data shows a growth rate of 3.47 ± 0.05 ppt/year in the past six years.
{"title":"The first satellite measurements of HFC-125 by the ACE-FTS: Long-term trends and distribution in the Earth’s upper troposphere and lower stratosphere","authors":"R. Dodangodage , P.F. Bernath , C. Boone , J.J. Harrison , M. Lecours , M. Schmidt , S.A. Montzka , I. Vimont , M. Crotwell","doi":"10.1016/j.jqsrt.2024.109218","DOIUrl":"10.1016/j.jqsrt.2024.109218","url":null,"abstract":"<div><div>HFC-125 (CF<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>CHF<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, pentafluoroethane) volume mixing ratios (VMRs) have been determined for the first time using infrared absorption spectra from the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) from 2004 to 2024. These VMRs provide global altitude-latitude VMR distributions. A VMR time series for HFC-125 has also been calculated and compared to values from in situ discrete flask measurements conducted by the National Oceanic and Atmospheric Administration Earth System Research Laboratory. The abundance of HFC-125 is currently experiencing exponential growth. ACE data shows a growth rate of 3.47 ± 0.05 ppt/year in the past six years.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109218"},"PeriodicalIF":2.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527346","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 : 2024-10-16DOI: 10.1016/j.jqsrt.2024.109217
Peter F. Bernath , Manish Bhusal
Version 5.2 SO data from the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) in low Earth orbit are used to determine global altitude–latitude abundance distributions. This new data set has SO volume mixing ratios (VMRs) from 11.5 to 39.5 km in altitude from February 2004 to July 2023. The average background SO abundance is plotted along with the abundance for four different seasons. These distributions show that there is a stratospheric source of SO that comes from the decline in sulfate aerosol abundance with increasing altitude. The visible and near-infrared photolysis of sulfuric acid (HSO) is the primary source of SO in the middle stratosphere. There is also a source of SO in the upper stratosphere and mesosphere. The Brewer-Dobson circulation enhances SO at higher altitudes, particularly by descent near the winter pole. The elevated abundance of SO near the poles originates from meteoric sources as well as UV photolysis of HSO in the mesosphere. Large volcanic eruptions release sulfur dioxide (SO) into the lower stratosphere, where it persists for several months.
{"title":"Sulfur dioxide sources in the stratosphere","authors":"Peter F. Bernath , Manish Bhusal","doi":"10.1016/j.jqsrt.2024.109217","DOIUrl":"10.1016/j.jqsrt.2024.109217","url":null,"abstract":"<div><div>Version 5.2 SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> data from the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) in low Earth orbit are used to determine global altitude–latitude abundance distributions. This new data set has SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> volume mixing ratios (VMRs) from 11.5 to 39.5 km in altitude from February 2004 to July 2023. The average background SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> abundance is plotted along with the abundance for four different seasons. These distributions show that there is a stratospheric source of SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> that comes from the decline in sulfate aerosol abundance with increasing altitude. The visible and near-infrared photolysis of sulfuric acid (H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>SO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>) is the primary source of SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> in the middle stratosphere. There is also a source of SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> in the upper stratosphere and mesosphere. The Brewer-Dobson circulation enhances SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> at higher altitudes, particularly by descent near the winter pole. The elevated abundance of SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> near the poles originates from meteoric sources as well as UV photolysis of H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>SO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> in the mesosphere. Large volcanic eruptions release sulfur dioxide (SO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>) into the lower stratosphere, where it persists for several months.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"330 ","pages":"Article 109217"},"PeriodicalIF":2.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527527","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号