This paper presents an extension of the previous spectroscopic investigations for the linear molecules HC3N and HC4H. For both species, new high-resolution data have been recorded and analyzed. As far as HC3N is concerned, the investigation of the ro-vibrational features has been based on the Fourier transform far-infrared spectra from our previous studies and on the mid-infrared spectra targeting the prominent overtone band recently recorded at the synchrotron facility SOLEIL with a resolution of 0.003 and 0.002 cm−1. Moreover, several hundreds of pure rotational transitions belonging to excited vibrational states were recorded in Bologna. The resonance network wrapping around the level and involving the (), (), (), and excited states has been thoroughly analyzed. A global ro-vibrational fit was then achieved for all the vibrational levels up to 1300 cm−1, therefore improving our previous analysis. For diacetylene, the stretching band around 3333 cm−1 was recorded by high-resolution FTIR spectroscopy at the synchrotron facility SOLEIL at a resolution of 0.005 cm−1. The accidental resonance affecting this band has been successfully analyzed and the number of observed and assigned ro-vibrational transitions was considerably extended. The present investigation allowed the integration of the existing line lists in the HITRAN database for both molecules. In particular, no information about the band of diacetylene was present in HITRAN before this study.
{"title":"An improved study of cyanoacetylene and diacetylene including the strong 2ν5 band of HC3N and ν4 band of HC4H","authors":"Luca Bizzocchi , Mattia Melosso , Filippo Tamassia , Martina Taddia , Francesca Tonolo , Silvia Alessandrini , Gabriele Panizzi , Michela Nonne , Marie-Aline Martin-Drumel , Olivier Pirali , Luca Dore , Iouli E. Gordon , Cristina Puzzarini","doi":"10.1016/j.jqsrt.2026.109879","DOIUrl":"10.1016/j.jqsrt.2026.109879","url":null,"abstract":"<div><div>This paper presents an extension of the previous spectroscopic investigations for the linear molecules HC<sub>3</sub>N and HC<sub>4</sub>H. For both species, new high-resolution data have been recorded and analyzed. As far as HC<sub>3</sub>N is concerned, the investigation of the ro-vibrational features has been based on the Fourier transform far-infrared spectra from our previous studies and on the mid-infrared spectra targeting the prominent <span><math><mrow><mn>2</mn><msub><mrow><mi>ν</mi></mrow><mrow><mn>5</mn></mrow></msub></mrow></math></span> overtone band recently recorded at the synchrotron facility SOLEIL with a resolution of 0.003 and 0.002<!--> <!-->cm<sup>−1</sup>. Moreover, several hundreds of pure rotational transitions belonging to excited vibrational states were recorded in Bologna. The resonance network wrapping around the <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>5</mn></mrow></msub><mo>=</mo><mn>2</mn></mrow></math></span> level and involving the (<span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>1</mn><mo>,</mo><msub><mrow><mi>v</mi></mrow><mrow><mn>7</mn></mrow></msub><mo>=</mo><mn>2</mn></mrow></math></span>), (<span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>6</mn></mrow></msub><mo>=</mo><mn>2</mn><mo>,</mo><msub><mrow><mi>v</mi></mrow><mrow><mn>7</mn></mrow></msub><mo>=</mo><mn>2</mn></mrow></math></span>), (<span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>5</mn></mrow></msub><mo>=</mo><mn>1</mn><mo>,</mo><msub><mrow><mi>v</mi></mrow><mrow><mn>7</mn></mrow></msub><mo>=</mo><mn>3</mn></mrow></math></span>), and <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>7</mn></mrow></msub><mo>=</mo><mn>6</mn></mrow></math></span> excited states has been thoroughly analyzed. A global ro-vibrational fit was then achieved for all the vibrational levels up to 1300<!--> <!-->cm<sup>−1</sup>, therefore improving our previous analysis. For diacetylene, the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> stretching band around 3333<!--> <!-->cm<sup>−1</sup> was recorded by high-resolution FTIR spectroscopy at the synchrotron facility SOLEIL at a resolution of 0.005<!--> <!-->cm<sup>−1</sup>. The accidental resonance affecting this band has been successfully analyzed and the number of observed and assigned ro-vibrational transitions was considerably extended. The present investigation allowed the integration of the existing line lists in the HITRAN database for both molecules. In particular, no information about the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> band of diacetylene was present in HITRAN before this study.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"357 ","pages":"Article 109879"},"PeriodicalIF":1.9,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147388348","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 : 2026-07-01Epub Date: 2026-03-05DOI: 10.1016/j.jqsrt.2026.109899
Yi Wang , Jinjun Liu , Rebekah Esmaili , Mark Schoeberl
Satellite nadir retrievals of Aerosol Optical Depth (AOD) cannot be made over clouds which can limit their use for near-real-time air-quality monitoring. We evaluate a simple time-series approach that increases AOD coverage over clouds by predicting short-term transport and filling gaps using Machine Learning (ML). We use a single-channel convolutional long short-term memory (ConvLSTM) sequence model trained on NOAA GOES-18 ABI AOD dataset. Predicted plumes reproduce observed spatial organization despite the presence of clouds, and when composited into the observed AOD field by filling missing pixels, the model provides spatially coherent AOD estimates over obscured regions. With longer lead times, predictions become smoother and high-AOD extremes are unrealistically suppressed, narrowing the dynamic range relative to observations. Motion, quantified by an AOD-weighted centroid, shows frame-to-frame step distances that are smaller than observed. The distances decline with time, indicating accumulated transport error and under-advection of filaments. In addition, scene-mean AOD and its standard deviation are lower in predictions than in observations and decrease further with longer lead time (in 20-min intervals between frames). Performance degrades with increasing lead time and during prolonged, widespread obscuration, and may be less reliable for abrupt aerosol regime shifts. We compare ML model gap filling with ordinary kriging anchored to observed edges: kriging yields the smoother fields and tends to elevate AOD over broader regions, whereas ML-based filling preserves plume organization, avoids some edge amplification, and produces fewer extremes. Overall, a ConvLSTM provides timely AOD nowcasts and substantially extends coverage for short lead times, although performance degrades with lead time.
气溶胶光学深度（AOD）的卫星最低点反演不能在云层上进行，这限制了它们在近实时空气质量监测中的应用。我们评估了一种简单的时间序列方法，该方法通过预测短期运输和使用机器学习（ML）填补空白来增加AOD在云上的覆盖。本文采用基于NOAA GOES-18 ABI AOD数据集训练的单通道卷积长短期记忆（ConvLSTM）序列模型。尽管存在云，但预测的羽流再现了观测到的空间组织，当通过填充缺失的像素将其合成到观测到的AOD场时，该模型提供了遮蔽区域上空间一致的AOD估计。由于提前期较长，预测变得更平稳，高aod极端值被不切实际地抑制，相对于观测值缩小了动态范围。运动，由aod加权质心量化，显示帧到帧的步距比观测到的要小。随着时间的推移，距离逐渐减小，表明输送误差的累积和细丝的欠平流。此外，场景平均AOD及其标准偏差在预测中比在观测中更低，并且随着提前时间的延长（帧间间隔20分钟）进一步降低。性能随着提前时间的增加和长时间、大范围的遮蔽而下降，并且对于突然的气溶胶状态变化可能不太可靠。我们将ML模型的间隙填充与锚定在观测边缘的普通克里格模型进行了比较：克里格模型产生更光滑的场，并倾向于在更广泛的区域上提升AOD，而基于ML的填充保留了羽流组织，避免了一些边缘放大，并且产生的极端情况更少。总的来说，ConvLSTM提供了及时的AOD临近预报，并在较短的交货时间内大大扩展了覆盖范围，尽管性能会随着交货时间的延长而下降。
{"title":"Extending geostationary satellite AOD coverage with a lightweight spatiotemporal sequence model","authors":"Yi Wang , Jinjun Liu , Rebekah Esmaili , Mark Schoeberl","doi":"10.1016/j.jqsrt.2026.109899","DOIUrl":"10.1016/j.jqsrt.2026.109899","url":null,"abstract":"<div><div>Satellite nadir retrievals of Aerosol Optical Depth (AOD) cannot be made over clouds which can limit their use for near-real-time air-quality monitoring. We evaluate a simple time-series approach that increases AOD coverage over clouds by predicting short-term transport and filling gaps using Machine Learning (ML). We use a single-channel convolutional long short-term memory (ConvLSTM) sequence model trained on NOAA GOES-18 ABI AOD dataset. Predicted plumes reproduce observed spatial organization despite the presence of clouds, and when composited into the observed AOD field by filling missing pixels, the model provides spatially coherent AOD estimates over obscured regions. With longer lead times, predictions become smoother and high-AOD extremes are unrealistically suppressed, narrowing the dynamic range relative to observations. Motion, quantified by an AOD-weighted centroid, shows frame-to-frame step distances that are smaller than observed. The distances decline with time, indicating accumulated transport error and under-advection of filaments. In addition, scene-mean AOD and its standard deviation are lower in predictions than in observations and decrease further with longer lead time (in 20-min intervals between frames). Performance degrades with increasing lead time and during prolonged, widespread obscuration, and may be less reliable for abrupt aerosol regime shifts. We compare ML model gap filling with ordinary kriging anchored to observed edges: kriging yields the smoother fields and tends to elevate AOD over broader regions, whereas ML-based filling preserves plume organization, avoids some edge amplification, and produces fewer extremes. Overall, a ConvLSTM provides timely AOD nowcasts and substantially extends coverage for short lead times, although performance degrades with lead time.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"357 ","pages":"Article 109899"},"PeriodicalIF":1.9,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147388347","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}
The profiles of nine key subTHz HO lines were recorded at various pressures and room temperature using two fundamentally different spectroscopic techniques. The beyond-Voigt line shape taking into account the speed-dependence of the collision relaxation rate was employed to analyze the high quality experimental recordings. Collisional broadening, shifting and their quadratic speed-dependence were measured for major atmospheric perturbers HO, N, O, and Ar. The found air-related line shape parameters can be used for updating atmospheric databases and propagation models.
{"title":"Beyond-Voigt collisional parameters of subTHz H2O lines for atmospheric applications","authors":"M.A. Koshelev, I.N. Vilkov, D.S. Makarov, G.Yu. Golubiatnikov, A.O. Koroleva, T.A. Galanina","doi":"10.1016/j.jqsrt.2026.109854","DOIUrl":"10.1016/j.jqsrt.2026.109854","url":null,"abstract":"<div><div>The profiles of nine key subTHz H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O lines were recorded at various pressures and room temperature using two fundamentally different spectroscopic techniques. The beyond-Voigt line shape taking into account the speed-dependence of the collision relaxation rate was employed to analyze the high quality experimental recordings. Collisional broadening, shifting and their quadratic speed-dependence were measured for major atmospheric perturbers H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O, N<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, O<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and Ar. The found air-related line shape parameters can be used for updating atmospheric databases and propagation models.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109854"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146071923","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 : 2026-04-01Epub Date: 2026-01-15DOI: 10.1016/j.jqsrt.2026.109807
I.E. Gordon , L.S. Rothman , R.J. Hargreaves , F.M. Gomez , T. Bertin , C. Hill , R.V. Kochanov , Y. Tan , P. Wcisło , V. Yu. Makhnev , P.F. Bernath , M. Birk , V. Boudon , A. Campargue , A. Coustenis , B.J. Drouin , R.R. Gamache , J.T. Hodges , D. Jacquemart , E.J. Mlawer , N.F. Zobov
The HITRAN database is a curated compilation of validated molecular spectroscopic parameters, established in the early 1970s. It is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of six major components. These components include the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimentally derived absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. Responding to community requests, HITRAN2024 also incorporates — for the first time — a water-vapor continuum model.
This paper describes the details of the choices of data and their compilation for the 2024 quadrennial edition of HITRAN. The HITRAN2024 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2020 (including various updates during the intervening years).
The extent of the updates of the line-by-line section in the HITRAN2024 edition ranges from updating a few lines of specific molecules/isotopologues to complete replacements of the lists, and also the introduction of additional isotopologues and six new (to HITRAN) molecules: H, CH, S, COFCl, HONO, ClNO. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. In addition, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often bringing the uncertainties down to unprecedented levels below 0.1%.
The HITRAN2024 edition is available through www.hitran.org as well as the HITRAN Application Programming Interface (HAPI). The functionality of the tools to work with the HITRAN data has been extended for the new edition.
{"title":"The HITRAN2024 molecular spectroscopic database","authors":"I.E. Gordon , L.S. Rothman , R.J. Hargreaves , F.M. Gomez , T. Bertin , C. Hill , R.V. Kochanov , Y. Tan , P. Wcisło , V. Yu. Makhnev , P.F. Bernath , M. Birk , V. Boudon , A. Campargue , A. Coustenis , B.J. Drouin , R.R. Gamache , J.T. Hodges , D. Jacquemart , E.J. Mlawer , N.F. Zobov","doi":"10.1016/j.jqsrt.2026.109807","DOIUrl":"10.1016/j.jqsrt.2026.109807","url":null,"abstract":"<div><div>The HITRAN database is a curated compilation of validated molecular spectroscopic parameters, established in the early 1970s. It is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of six major components. These components include the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimentally derived absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. Responding to community requests, HITRAN2024 also incorporates — for the first time — a water-vapor continuum model.</div><div>This paper describes the details of the choices of data and their compilation for the 2024 quadrennial edition of HITRAN. The HITRAN2024 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2020 (including various updates during the intervening years).</div><div>The extent of the updates of the line-by-line section in the HITRAN2024 edition ranges from updating a few lines of specific molecules/isotopologues to complete replacements of the lists, and also the introduction of additional isotopologues and six new (to HITRAN) molecules: H<span><math><msubsup><mrow></mrow><mrow><mn>3</mn></mrow><mrow><mo>+</mo></mrow></msubsup></math></span>, CH<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>, S<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, COFCl, HONO, ClNO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. In addition, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often bringing the uncertainties down to unprecedented levels below 0.1%.</div><div>The HITRAN2024 edition is available through <span><span>www.hitran.org</span><svg><path></path></svg></span> as well as the HITRAN Application Programming Interface (HAPI). The functionality of the tools to work with the HITRAN data has been extended for the new edition.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109807"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995424","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 : 2026-04-01Epub Date: 2026-01-19DOI: 10.1016/j.jqsrt.2026.109835
Yao Sun , Jingxin Zhang , Lan Wu , Chonghui Cheng , Weize Li , Kai Zhang , Xueping Wan , Wentai Chen , Zhiji Deng , Ming Liu , Miao Cheng , Zhewei Fu , Dong Liu
Observations of water cloud optical and microphysical properties are indispensable for quantifying its radiative forcing and improving predictions of climate change. In this paper, comparisons between two lidar-based techniques for water cloud detection, i.e., dual-field-of-view high-spectral-resolution lidar (dual-FOV HSRL) and the polarized Mie-scattering lidar (PML), with consideration of multiple scattering effects are presented. The retrieval results from Monte Carlo (MC) simulations with both techniques are compared, demonstrating that the extinction coefficient (αc) and effective radius (reff) retrieved by dual-FOV HSRL exhibit smaller root mean square error (RMSE) and relative bias values than those from PML under a typical water cloud scenario. A case study of the measurements performed with Zhejiang University high-spectral-resolution lidar for aerosol and cloud (ZJU-HSRL) system at Hangzhou, China, is presented, and the results show that the dual-FOV HSRL technique is a more stable and flexible approach for profiling realistic water cloud vertical structures, especially under the influence of dry air entrainment.
{"title":"Development of ZJU high-spectral-resolution lidar for aerosol and cloud: Comparison between dual-FOV HSRL and polarized lidar for water cloud detection","authors":"Yao Sun , Jingxin Zhang , Lan Wu , Chonghui Cheng , Weize Li , Kai Zhang , Xueping Wan , Wentai Chen , Zhiji Deng , Ming Liu , Miao Cheng , Zhewei Fu , Dong Liu","doi":"10.1016/j.jqsrt.2026.109835","DOIUrl":"10.1016/j.jqsrt.2026.109835","url":null,"abstract":"<div><div>Observations of water cloud optical and microphysical properties are indispensable for quantifying its radiative forcing and improving predictions of climate change. In this paper, comparisons between two lidar-based techniques for water cloud detection, i.e., dual-field-of-view high-spectral-resolution lidar (dual-FOV HSRL) and the polarized Mie-scattering lidar (PML), with consideration of multiple scattering effects are presented. The retrieval results from Monte Carlo (MC) simulations with both techniques are compared, demonstrating that the extinction coefficient (<em>α<sub>c</sub></em>) and effective radius (<em>r<sub>eff</sub></em>) retrieved by dual-FOV HSRL exhibit smaller root mean square error (<em>RMSE</em>) and relative bias values than those from PML under a typical water cloud scenario. A case study of the measurements performed with Zhejiang University high-spectral-resolution lidar for aerosol and cloud (ZJU-HSRL) system at Hangzhou, China, is presented, and the results show that the dual-FOV HSRL technique is a more stable and flexible approach for profiling realistic water cloud vertical structures, especially under the influence of dry air entrainment.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109835"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001497","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}
The room-temperature continuum absorption of pure methane and of its mixture with nitrogen and carbon dioxide was measured in the millimeter wavelength range using resonator spectrometer. The line wings contribution to the continuum was estimated to be weak. The bimolecular nature of the observed continuum was confirmed by both the expected pressure dependences and the agreement with trajectory-based simulation.
{"title":"Continuum absorption of millimeter waves by CH4-X (X=CH4, N2, CO2)","authors":"A.O. Koroleva , T.A. Galanina , I.S. Amerkhanov , E.A. Serov , A.Yu. Sekacheva , M.A. Koshelev , D.N. Chistikov , A.A. Finenko , M.Yu. Tretyakov","doi":"10.1016/j.jqsrt.2026.109841","DOIUrl":"10.1016/j.jqsrt.2026.109841","url":null,"abstract":"<div><div>The room-temperature continuum absorption of pure methane and of its mixture with nitrogen and carbon dioxide was measured in the millimeter wavelength range using resonator spectrometer. The line wings contribution to the continuum was estimated to be weak. The bimolecular nature of the observed continuum was confirmed by both the expected pressure dependences and the agreement with trajectory-based simulation.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109841"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048523","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}
<div><div>The high resolution submillimeter wave spectra of methylene chloride (earlier recorded in the I. Physikalisches Institut, Universität zu Köln (Germany) and Laboratoire PhLAM, Université de Lille (France) in the wide spectral region of 0.075–1.1 THz) were analyzed with the goal of high accurate description of the quadrupole-rotational structures of the <sup>12</sup>CH<sub>2</sub><sup>35</sup>Cl<sup>37</sup>Cl species in the (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) and (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2) vibrational states. Assignment and analysis of transitions was made in the frame of the Watson’s Hamiltonian in <span><math><mrow><mi>A</mi><mo>−</mo></mrow></math></span>reduction and <span><math><mrow><msup><mrow><mi>I</mi></mrow><mrow><mi>r</mi></mrow></msup><mo>−</mo></mrow></math></span> representation with the use of the ASYMTOPTPU computer code and SPFIT/SPCAT package of Pickett. The 4983 unresolved lines (4088 transitions) in the excited (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) vibrational state and 842 lines (1420 transitions) in the (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2)) vibrational state with the maximum values of quantum number <span><math><msup><mrow><mi>J</mi></mrow><mrow><mtext>max</mtext></mrow></msup></math></span> = 95/79 and <span><math><msubsup><mrow><mi>K</mi></mrow><mrow><mi>a</mi></mrow><mrow><mtext>max</mtext></mrow></msubsup></math></span> = 19/19 for the (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) and (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2) vibrational states were assigned in the experimental spectra. Weighted fit of the rotational and centrifugal distortion parameters, as well as, of the quadrupole splitting parameters was made. The obtained from the fit 19/16 rotational and centrifugal distortion parameters reproduces values of the 4983/842 experimental line positions (4088/1420 transitions) with the <span><math><msub><mrow><mi>d</mi></mrow><mrow><mtext>rms</mtext></mrow></msub></math></span> = 21/26 kHz for the states (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) and (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2). Comparison with the rotational and centrifugal distortion parameters known in the literature is made and shown that the latter reproduce the same (assigned in the present study) set of the experimental line positions with the <span><math><msub><mrow><mi>d</mi></mrow><mrow><mtext>rms</mtext></mrow></msub></math></span> values which are considerably worse in comparison with the results of the present study. As to the quadrupole coupling <span><math><mrow><mi>χ</mi><mo>−</mo></mrow></math></span>parameters,
{"title":"High accurate analysis of the excited (v4 = 1) and (v4 = 2) vibrational states of 12CH235Cl37Cl in the region up to 1.1 THz","authors":"O.N. Ulenikov, O.V. Gromova, E.S. Bekhtereva, Yu.V. Khudyakova, V.E. Nikolaeva","doi":"10.1016/j.jqsrt.2026.109832","DOIUrl":"10.1016/j.jqsrt.2026.109832","url":null,"abstract":"<div><div>The high resolution submillimeter wave spectra of methylene chloride (earlier recorded in the I. Physikalisches Institut, Universität zu Köln (Germany) and Laboratoire PhLAM, Université de Lille (France) in the wide spectral region of 0.075–1.1 THz) were analyzed with the goal of high accurate description of the quadrupole-rotational structures of the <sup>12</sup>CH<sub>2</sub><sup>35</sup>Cl<sup>37</sup>Cl species in the (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) and (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2) vibrational states. Assignment and analysis of transitions was made in the frame of the Watson’s Hamiltonian in <span><math><mrow><mi>A</mi><mo>−</mo></mrow></math></span>reduction and <span><math><mrow><msup><mrow><mi>I</mi></mrow><mrow><mi>r</mi></mrow></msup><mo>−</mo></mrow></math></span> representation with the use of the ASYMTOPTPU computer code and SPFIT/SPCAT package of Pickett. The 4983 unresolved lines (4088 transitions) in the excited (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) vibrational state and 842 lines (1420 transitions) in the (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2)) vibrational state with the maximum values of quantum number <span><math><msup><mrow><mi>J</mi></mrow><mrow><mtext>max</mtext></mrow></msup></math></span> = 95/79 and <span><math><msubsup><mrow><mi>K</mi></mrow><mrow><mi>a</mi></mrow><mrow><mtext>max</mtext></mrow></msubsup></math></span> = 19/19 for the (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) and (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2) vibrational states were assigned in the experimental spectra. Weighted fit of the rotational and centrifugal distortion parameters, as well as, of the quadrupole splitting parameters was made. The obtained from the fit 19/16 rotational and centrifugal distortion parameters reproduces values of the 4983/842 experimental line positions (4088/1420 transitions) with the <span><math><msub><mrow><mi>d</mi></mrow><mrow><mtext>rms</mtext></mrow></msub></math></span> = 21/26 kHz for the states (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 1) and (<span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> = 2). Comparison with the rotational and centrifugal distortion parameters known in the literature is made and shown that the latter reproduce the same (assigned in the present study) set of the experimental line positions with the <span><math><msub><mrow><mi>d</mi></mrow><mrow><mtext>rms</mtext></mrow></msub></math></span> values which are considerably worse in comparison with the results of the present study. As to the quadrupole coupling <span><math><mrow><mi>χ</mi><mo>−</mo></mrow></math></span>parameters, ","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109832"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048524","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 : 2026-04-01Epub Date: 2026-01-23DOI: 10.1016/j.jqsrt.2026.109834
Gérard Gouesbet , Leonardo A. Ambrosio , Jhonas O. de Sarro
We discuss a synthesis between (i) a generic formulation of generalized Lorenz–Mie theory (more generally of arbitrary light scattering theories) for an arbitrary scatterer illuminated by one laser pulse and (ii) a polychromatic generalized Lorenz–Mie theory in the strict sense, i.e. for a spherical homogeneous spherical particle, illuminated by several polychromatic non-continuous beams. The synthesis then takes the form of generic polychromatic light scattering theories for particles of arbitrary shapes and morphologies illuminated by several laser pulses, or train of pulses. Although the present work is discussed in an electromagnetic framework, it can be adapted to scalar, in particular acoustical, scattering.
{"title":"Generic polychromatic light scattering theories for particles of arbitrary shapes and morphologies illuminated by laser pulses","authors":"Gérard Gouesbet , Leonardo A. Ambrosio , Jhonas O. de Sarro","doi":"10.1016/j.jqsrt.2026.109834","DOIUrl":"10.1016/j.jqsrt.2026.109834","url":null,"abstract":"<div><div>We discuss a synthesis between (i) a generic formulation of generalized Lorenz–Mie theory (more generally of arbitrary light scattering theories) for an arbitrary scatterer illuminated by one laser pulse and (ii) a polychromatic generalized Lorenz–Mie theory in the strict sense, i.e. for a spherical homogeneous spherical particle, illuminated by several polychromatic non-continuous beams. The synthesis then takes the form of generic polychromatic light scattering theories for particles of arbitrary shapes and morphologies illuminated by several laser pulses, or train of pulses. Although the present work is discussed in an electromagnetic framework, it can be adapted to scalar, in particular acoustical, scattering.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109834"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033172","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 : 2026-04-01Epub Date: 2026-01-14DOI: 10.1016/j.jqsrt.2026.109831
Adrian Hjältén , Vinicius Silva de Oliveira , Michael Rey , Isak Silander , Kevin K. Lehmann , Aleksandra Foltynowicz
We use sub-Doppler optical-optical double-resonance (OODR) spectroscopy with a 3.3 µm single-frequency pump and a cavity-enhanced 1.65 µm comb probe to measure 33 ladder-type (3ν3 ← ν3) and 8 V-type (2ν3) transitions in the 5880–6090 cm-1 range of methane, reaching states with rovibrational E symmetry in the region of the P6 and P4 polyads, respectively. We assign the ladder-type transitions using new Hamiltonian predictions and the ExoMol line list, and the V-type transitions using the new Hamiltonian, ExoMol, HITRAN2020, and the WKLMC line lists. While 7 of the states in the 3ν3 range have been previously observed either in earlier OODR work (without cavity enhancement) with 1.5 MHz accuracy or in FTIR measurements of cold bands with 150 MHz resolution, the states reported here have uncertainties down to 150 kHz (5 × 10–6 cm-1). The E-symmetry states exhibit first-order Stark splitting, which will be reported in our future work.
{"title":"Measurement and assignment of E-symmetry states in the 6010-6110 cm−1 and 8940-9150 cm−1 ranges of methane using optical frequency comb double-resonance spectroscopy","authors":"Adrian Hjältén , Vinicius Silva de Oliveira , Michael Rey , Isak Silander , Kevin K. Lehmann , Aleksandra Foltynowicz","doi":"10.1016/j.jqsrt.2026.109831","DOIUrl":"10.1016/j.jqsrt.2026.109831","url":null,"abstract":"<div><div>We use sub-Doppler optical-optical double-resonance (OODR) spectroscopy with a 3.3 µm single-frequency pump and a cavity-enhanced 1.65 µm comb probe to measure 33 ladder-type (3ν<sub>3</sub> ← ν<sub>3</sub>) and 8 V-type (2ν<sub>3</sub>) transitions in the 5880–6090 cm<sup>-1</sup> range of methane, reaching states with rovibrational E symmetry in the region of the <em>P</em>6 and <em>P</em>4 polyads, respectively. We assign the ladder-type transitions using new Hamiltonian predictions and the ExoMol line list, and the V-type transitions using the new Hamiltonian, ExoMol, HITRAN2020, and the WKLMC line lists. While 7 of the states in the 3ν<sub>3</sub> range have been previously observed either in earlier OODR work (without cavity enhancement) with 1.5 MHz accuracy or in FTIR measurements of cold bands with 150 MHz resolution, the states reported here have uncertainties down to 150 kHz (5 × 10<sup>–6</sup> cm<sup>-1</sup>). The E-symmetry states exhibit first-order Stark splitting, which will be reported in our future work.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109831"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995113","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 : 2026-04-01Epub Date: 2026-01-19DOI: 10.1016/j.jqsrt.2026.109836
Oleg S. Ugolnikov
The simple 3-D radiative transfer model of the Earth’s atmosphere is developed for numerical comparison of direct solar radiation and limb scattering background at the definite middle or upper atmospheric layer during the deep twilight period. This model enables the quantification of the multiple scattering contribution in the field of high-altitude clouds, such as polar stratospheric and noctilucent clouds. This is the factor that can influence the results of altitude and microphysical particle study based on the approximation of single scattering. The possible errors caused by this effect are estimated together with the contribution of multiple scattering for different altitudes of the clouds, wavelengths, and solar zenith angles. The results are interpreted geometrically and optically, the color effects observed for noctilucent clouds are described.
{"title":"Multiple scattering effects in noctilucent clouds: Numerical estimation and application to altitude and particle size measurements","authors":"Oleg S. Ugolnikov","doi":"10.1016/j.jqsrt.2026.109836","DOIUrl":"10.1016/j.jqsrt.2026.109836","url":null,"abstract":"<div><div>The simple 3-D radiative transfer model of the Earth’s atmosphere is developed for numerical comparison of direct solar radiation and limb scattering background at the definite middle or upper atmospheric layer during the deep twilight period. This model enables the quantification of the multiple scattering contribution in the field of high-altitude clouds, such as polar stratospheric and noctilucent clouds. This is the factor that can influence the results of altitude and microphysical particle study based on the approximation of single scattering. The possible errors caused by this effect are estimated together with the contribution of multiple scattering for different altitudes of the clouds, wavelengths, and solar zenith angles. The results are interpreted geometrically and optically, the color effects observed for noctilucent clouds are described.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"353 ","pages":"Article 109836"},"PeriodicalIF":1.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146000783","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}
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