Journal of Quantitative Spectroscopy & Radiative Transfer最新文献

{"title":"Methyl bromide spectral lines broadening by collision with N2","authors":"Ikbel Majdi ,&nbsp;Driss ben Abdallah ,&nbsp;Jamel Salem ,&nbsp;Muneerah Mogren Al-Mogren ,&nbsp;Hassen Aroui ,&nbsp;Majdi Hochlaf","doi":"10.1016/j.jqsrt.2025.109624","DOIUrl":"10.1016/j.jqsrt.2025.109624","url":null,"abstract":"<div><div>In this study, we investigated the broadening of methyl bromide (CH₃Br) rotational lines induced by collision with nitrogen (N₂), using a newly developed ab initio multi-dimensional potential energy surface (PES) for the CH₃Br–N₂ van der Waals complex. The radial coefficients of the PES were optimized through a least-squares fitting procedure and then adjusted using fractional functions to enable integration into our collisional broadening computation code. Then, we applied the semi-classical Modified Robert and Bonamy (MRB) model, enhanced by the exact trajectory approach, to calculate the N₂-induced broadening coefficients for CH₃Br ro-vibrational lines at room temperature. Results are provided for various branches of the parallel ν₂ vibrational band of CH₃Br. Our results are roughly consistent with the available experimental data, but through this work, we aim to highlight the weaknesses of the MRB model. Our findings are useful for more understanding and clearer delineation of the limitations of the MRB model.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109624"},"PeriodicalIF":1.9,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841828","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}

{"title":"Modulation transfer spectroscopy of 7Li D1 line","authors":"Leonid Khalutornykh ,&nbsp;Sergey Saakyan ,&nbsp;Alexander Nazarov ,&nbsp;Boris B. Zelener","doi":"10.1016/j.jqsrt.2025.109594","DOIUrl":"10.1016/j.jqsrt.2025.109594","url":null,"abstract":"<div><div>We present the first implementation of modulation transfer spectroscopy (MTS) on the D1 line of <span><math><msup><mrow></mrow><mrow><mn>7</mn></mrow></msup></math></span>Li, carried out in a compact heat-pipe vapor cell with cold windows. By varying the pump and probe intensities and polarization configurations, we systematically map the MTS error-signal amplitude, effective linewidth, and slope for the ground-state crossover resonance <span><math><mrow><mi>F</mi><mo>=</mo><mn>1</mn><mo>×</mo><mn>2</mn><mo>→</mo><msup><mrow><mi>F</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>=</mo><mn>2</mn></mrow></math></span>. We observe Rabi-induced power broadening and identify optimal conditions for laser frequency stabilization via tightly focused beams with total power below 1 mW. The lin<span><math><mo>⊥</mo></math></span>lin polarization configuration yields a sharp, symmetric, high-contrast error signal with a maximal slope. Our findings establish the MTS spectrum of the <span><math><msup><mrow></mrow><mrow><mn>7</mn></mrow></msup></math></span>Li D1 line transitions as a reliable frequency reference for quantum technology and ultracold atom experiments, particularly in scenarios where frequency stabilization must be achieved with low laser optical power.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109594"},"PeriodicalIF":1.9,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780102","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}

{"title":"Light scattering by droplets containing small chiral particles","authors":"Yehor Surkov ,&nbsp;Yuriy Shkuratov ,&nbsp;Vadym Kaydash ,&nbsp;Yong-Le Pan ,&nbsp;Aimable Kalume ,&nbsp;Yuli Heinson ,&nbsp;Chuji Wang ,&nbsp;Yongxiang Hu ,&nbsp;Gorden Videen","doi":"10.1016/j.jqsrt.2025.109604","DOIUrl":"10.1016/j.jqsrt.2025.109604","url":null,"abstract":"<div><div>We calculate the light-scattering properties of methane and water droplets containing spiral particles, which may simulate the presence of biological or prebiotic components. Such aerosols are present in the atmosphere of Earth and Titan. We focus our studies on the circular-polarization Mueller-matrix element М₁₄ that has been considered a tool for remote sensing biological materials. Unlike the non-zero elements of spheres (M₁₁, M₁₂, M₂₁, M₂₂, M₃₃, M₃₄, M₄₃, and M₄₄), the signals of the remaining off-diagonal elements (M₁₃, M₁₄, M₂₃, M₂₄, M₃₁, M₃₂, M₄₁, and M₄₂) do not show any regions of preferential positive or negative polarization. While our simulations show the М₁₄ element reaching 70% polarization, when orientation averaging is performed on this signal, it is reduced by over an order of magnitude. Such a reduction in signal does not occur for the non-zero elements of spheres, which have a stronger dependence on the spherical interface. Our simulations suggest that the circular-polarization opposition effect appears to be present in such particles, but it is difficult to discern because of the oscillations of the circular intensity differential scattering parameter (CIDS) signal.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109604"},"PeriodicalIF":1.9,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763781","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}

{"title":"Juxtaposing the fourth order vibrational operator perturbation theory CVPT(4) and the adaptive VCI (A-VCI): Accuracy, vibrational resonances and polyads of C2H4 and C2D4","authors":"Vincent Le Bris ,&nbsp;Sergey V. Krasnoshchekov ,&nbsp;Egor O. Dobrolyubov ,&nbsp;Ilya M. Efremov ,&nbsp;Igor V. Polyakov ,&nbsp;Olivier Coulaud ,&nbsp;Didier Bégué","doi":"10.1016/j.jqsrt.2025.109586","DOIUrl":"10.1016/j.jqsrt.2025.109586","url":null,"abstract":"&lt;div&gt;&lt;div&gt;&lt;em&gt;Ab initio&lt;/em&gt; prediction of anharmonic vibrational spectra produces an increasing computational overhead for larger molecules, requesting a balance between an accuracy and resources. Two complementary fundamental quantum mechanical approaches, the perturbative and variational, have various strong and weak features, depending on a specific target problem. The vibrational perturbation theory (VPT) treats weak couplings and strong resonances separately, relying on somewhat artificial criteria. In contrast, the more precise but computationally intense variational configuration interaction (VCI) method treats all couplings in universal manner. The active ongoing development of approaches to solving vibrational problems requires an update of comparative benchmarks, helping to choose the best theoretical tools for a particular target. In this work, the performance of two particular modern implementations of these methods was juxtaposed: the second and fourth order operator canonical perturbation theory CVPT(2,4) and a recently proposed adaptive vibrational configuration interaction method (A-VCI). Two practically important C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;4&lt;/sub&gt; and C&lt;sub&gt;2&lt;/sub&gt;D&lt;sub&gt;4&lt;/sub&gt; molecules and an accurate CCSD(T)/cc-pVQZ four-body sextic normal mode PES were employed for benchmarking. The comprehensive picture of vibrational resonances and the polyad quantum number was revealed in the form: &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;[&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;]&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;11&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. A new quadratic resonance criterion &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;|&lt;/mo&gt;&lt;/mrow&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;V&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mo&gt;∑&lt;/mo&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/mr","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109586"},"PeriodicalIF":1.9,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144781272","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}

{"title":"Water vapor self-continuum measurements in the infrared atmospheric window and ν2 band region (700–2000 cm−1)","authors":"Christian Röske,&nbsp;Manfred Birk,&nbsp;Georg Wagner","doi":"10.1016/j.jqsrt.2025.109602","DOIUrl":"10.1016/j.jqsrt.2025.109602","url":null,"abstract":"<div><div>Pure water vapor measurements were conducted over a temperature range of 278.7–353.0 K and a wavenumber range of 700–2000 cm⁻¹ using a commercial Bruker IFS 125HR Fourier-transform spectrometer with a multi-reflection cell. Line parameters and continuum contributions were derived from the same spectra.</div><div>In the out-of-band region 700–1350 cm⁻¹, the H₂O self-continuum was determined at ambient temperature. The measured continuum shows good agreement with a narrow-band measurement at 1185 cm⁻¹. In line with measurements that led to the development of MT_CKD 4.2, it was found that the self-continuum is substantially weaker than had been assumed for decades. Compared to MT_CKD 4.2, even lower values by as much as 17% were found below 1000 cm⁻¹. Since the out-of-band continuum overlaps with the infrared atmospheric window, which is of high importance for the Earth’s radiation budget, “clear-sky” radiative transfer calculations were performed using both MT_CKD 4.2 and the data of this study. The largest difference was found for tropical atmosphere, where this study yielded a 0.31 W m⁻² higher outgoing longwave radiation.</div><div>The self-continua in the in-band region around ν₂ were fitted using a model that combines bound and quasi-bound dimer spectra, enabling the determination of temperature-dependent equilibrium constants and corresponding formation enthalpies: ΔH_296K,Db = −1202(32) cm⁻¹ and ΔH_296K,Dq = −748(168) cm⁻¹. The sum of the equilibrium constants, K_Db(T) + K_Dq(T), exceeds the value predicted by second virial coefficients, well beyond the uncertainty margin.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109602"},"PeriodicalIF":1.9,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060090","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}

{"title":"Changes of optical properties of two carbonaceous nanoparticles upon their coalescence: Computations at the atomistic level","authors":"N. Brosseau-Habert ,&nbsp;F. Miradji ,&nbsp;M. Devel ,&nbsp;S. Picaud","doi":"10.1016/j.jqsrt.2025.109592","DOIUrl":"10.1016/j.jqsrt.2025.109592","url":null,"abstract":"<div><div>Once emitted into the atmosphere, soot nanoparticles undergo ageing processes during which they may collide and form aggregates, possibly modifying their physico-chemical properties. Here, we especially focus on their optical properties and the Dynamic Atomic Dipole Interaction (DADI) approach has been used to calculate the refractive index and the mass absorption cross section of two carbonaceous nanoparticles modeling soot. Three typical situations have been considered: separated particles, particles just in contact, interpenetrated particles. Molecular dynamics simulations based on a reactive interatomic interaction potential have been used to get the atomic coordinates in the three configurations considered and the graphite parametrization has been used for defining the polarizability tensors of the carbon atoms. The results of the DADI calculations show that the interpenetration of the nanoparticles actually modifies both their refractive index and their mass absorption cross section with respect to well-separated particles. Because the corresponding changes are shown to be tightly bound to local modifications of the close neighborhood of the carbon atoms, the present study emphasizes that an as precise as possible description of the coalescence process at the atomic scale is required to better quantify the influence of aggregation processes on the optical properties of carbonaceous nanoparticles. In addition, calculations at the atomic scale via the DADI method allow the computation of refractive indices taking into account the local modifications of the particles, which are shown to be then usable as inputs in macroscopic models, such as T-matrix. This would certainly help at better assessing, e.g., the actual impact of soot on climate.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109592"},"PeriodicalIF":1.9,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144756735","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}

{"title":"Theoretical and experimental electron collisions broadening parameters for several Sc II spectral lines of industrial and astrophysical interest","authors":"Lucía Isidoro-García ,&nbsp;Isabel de Andrés-García ,&nbsp;Juan Porro ,&nbsp;Francisco Fernández ,&nbsp;Cristóbal Colón","doi":"10.1016/j.jqsrt.2025.109587","DOIUrl":"10.1016/j.jqsrt.2025.109587","url":null,"abstract":"<div><div>Electron collision broadening parameters of 9 singly ionized scandium spectral lines (and 1 neutral scandium spectral line) were experimentally measured in laser-induced breakdown experiments using a Q-switched Nd:YAG laser focused on Pb-Sc alloy samples. Furthermore, calculations of these parameters were performed for 56 singly ionized scandium spectral lines in the semi-empirical Griem approach using the Gaunt factors proposed by Van Regemorter and those proposed by Douglas H. Sampson.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109587"},"PeriodicalIF":2.3,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713847","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}

{"title":"Doubly excited (v4=2) vibrational state of 12CH2 35Cl2: Centrifugal distortion and quadrupole splittings in the submillimeter wave spectra up to 1.1 THz","authors":"O.N. Ulenikov,&nbsp;O.V. Gromova,&nbsp;E.S. Bekhtereva,&nbsp;V.E. Nikolaeva,&nbsp;E.D. Gorbacheva","doi":"10.1016/j.jqsrt.2025.109585","DOIUrl":"10.1016/j.jqsrt.2025.109585","url":null,"abstract":"<div><div>The high resolution submillimeter wave spectra of the <span><math><msup><mrow></mrow><mrow><mn>12</mn></mrow></msup></math></span>CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> <span><math><msup><mrow></mrow><mrow><mn>35</mn></mrow></msup></math></span>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> methylene chloride (six spectra were recorded in different parts of the 0.075–1.1 THz spectral region in the I. Physikalisches Institut, Universität zu Köln (Germany) and Laboratoire PhLAM, Université de Lille (France)) were analyzed in the frame of 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 SPFIT/SPCAT package of Pickett. The 2368 unresolved lines (including 878 peripheral lines of triplets) with the maximum values of quantum number <span><math><mrow><msup><mrow><mi>J</mi></mrow><mrow><mtext>max</mtext></mrow></msup><mo>=</mo><mn>83</mn></mrow></math></span> and <span><math><mrow><msubsup><mrow><mi>K</mi></mrow><mrow><mi>a</mi></mrow><mrow><mtext>max</mtext></mrow></msubsup><mo>=</mo><mn>19</mn></mrow></math></span> were assigned in the experimental spectra to the <span><math><mrow><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>2</mn><mo>)</mo></mrow></math></span> vibrational state. Weighted fit of the rotational and centrifugal distortion parameters, as well as, of the nuclear quadrupole splitting parameters was made. The eleven rotational and centrifugal distortion parameters and three nuclear quadrupole coupling parameters obtained from the fit reproduce values of the experimental multiplet centers with the root mean square deviation of 36 kHz and of the experimental peripheral lines of triplets with <span><math><mrow><msub><mrow><mi>d</mi></mrow><mrow><mtext>rms</mtext></mrow></msub><mo>=</mo><mn>47</mn></mrow></math></span> kHz. Comparison with the rotational and centrifugal distortion parameters of the <span><math><mrow><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>2</mn><mo>)</mo></mrow></math></span> vibrational state known in the literature is made and shown that they reproduce the same set of the experimental line positions with <span><math><msub><mrow><mi>d</mi></mrow><mrow><mtext>rms</mtext></mrow></msub></math></span> that is 130 times 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, it was found that the three <span><math><mrow><mi>χ</mi><mo>−</mo></mrow></math></span>parameters obtained in the fit correlate very well with the corresponding parameters from the recent paper by Z. Kisiel (J Mol Spectrosc 2024;406:111954).</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109585"},"PeriodicalIF":2.3,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670113","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}

{"title":"An unstructured lattice Boltzmann method for numerical simulation of radiative transfer in porous media","authors":"Caiyun Wang,&nbsp;Xiaochuan Liu,&nbsp;Mingqi Liu,&nbsp;Yijie Wei,&nbsp;Yong Huang","doi":"10.1016/j.jqsrt.2025.109591","DOIUrl":"10.1016/j.jqsrt.2025.109591","url":null,"abstract":"<div><div>An unstructured lattice Boltzmann method for simulating radiative transfer in porous media at the pore scale is developed based on Chapman-Enskog analysis, Taylor expansion, and finite-volume discretization. The unstructured lattice Boltzmann method achieves an order of magnitude improvement in efficiency over the Monte Carlo method while maintaining comparable accuracy in two-dimensional benchmark cases. Utilizing the developed unstructured lattice Boltzmann method, the effects of skeleton surface emissivity, cross-sectional number, shape, and size on radiative transfer are investigated. Results reveal that skeleton emissivity significantly influences temperature and heat flux distribution, while cross-sectional geometry affects temperature uniformity, especially for structures with fewer pores. The findings underscore the importance of balancing key parameters for optimal thermal radiation performance in porous media. The unstructured lattice Boltzmann method presents a promising tool for advancing the understanding of radiative transfer in complex porous systems.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109591"},"PeriodicalIF":2.3,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670116","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}

{"title":"Fine- and hyperfine structure semi-empirical studies of singly ionized niobium. Even-parity configurations system","authors":"J. Ruczkowski ,&nbsp;M. Elantkowska ,&nbsp;M. Klempka","doi":"10.1016/j.jqsrt.2025.109583","DOIUrl":"10.1016/j.jqsrt.2025.109583","url":null,"abstract":"<div><div>We report the results of semi-empirical calculations of the fine structure (<em>fs</em>) and the hyperfine structure (<em>hfs</em>) for the even-parity level system of the niobium ion (Nb II), using all available experimental data. The calculations carried out showed, in most cases, very good agreement, within or slightly above the experimental uncertainty, between the 168 experimental values of the magnetic dipole <em>hfs A</em> constants and the calculated ones. The predicted energies of electronic levels, together with their Landé <span><math><msub><mrow><mi>g</mi></mrow><mrow><mi>J</mi></mrow></msub></math></span> factors, along with the <em>hfs</em> <span><math><mi>A</mi></math></span> constants for unknown levels, are also provided.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"346 ","pages":"Article 109583"},"PeriodicalIF":2.3,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670118","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}