Journal of Quantitative Spectroscopy & Radiative Transfer最新文献

{"title":"Scattering by a plasma anisotropic coated sphere located in an off-axis Zero-order Bessel beam","authors":"Zheng Jun Li ,&nbsp;Yu Feng Zhou ,&nbsp;Qing Chao Shang ,&nbsp;Tan Qu ,&nbsp;Zhen Sen Wu","doi":"10.1016/j.jqsrt.2025.109647","DOIUrl":"10.1016/j.jqsrt.2025.109647","url":null,"abstract":"<div><div>Based on the Generalized Lorenz–Mie theory (GLMT), electromagnetic scattering of a plasma anisotropic coated sphere illuminated by an off-axis Zero-order Bessel beam (ZOBB) is investigated. The expansion expressions of the ZOBB are given in terms of the spherical vector wave functions (SVWFs) and the expansion coefficients are derived using the orthogonality of associated Legendre function and exponential function. By introducing the Fourier transform, the electromagnetic (EM) fields in the plasma anisotropic layer are expressed as the addition of the first and the second SVWFs. The scattering coefficients are analytically derived by applying the continuous tangential boundary conditions to each interface among the internal isotropic dielectric or conductor sphere, the anisotropic shell, and the free space. The accuracy of the theory and codes are verified by comparing the numerical results reduced to the special cases of a plane wave incidence and a plasma anisotropic sphere with results from references. The effects of the conical angle, the beam center position, coating thickness and dielectric parameters on the Radar cross section (RCS) are analyzed. The applications of this theoretical development in the fields of target shielding, and anti-radar coatings are numerically discussed.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109647"},"PeriodicalIF":1.9,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144919872","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":"Impact of spatial topology and nitrogen atoms embedding in π-conjugated chromophores on their UV–VIS and IR spectra","authors":"Mikhail V. Vener ,&nbsp;Andrey V. Stolyarov","doi":"10.1016/j.jqsrt.2025.109646","DOIUrl":"10.1016/j.jqsrt.2025.109646","url":null,"abstract":"<div><div>A comparative study of <em>π</em>-conjugated chromophores of interest in astrochemistry is carried out using density functional theory (DFT) and time-dependent DFT. The point of the study is the simultaneous systematic evaluation of both UV/Visible and IR spectra by using of the same B3LYP functional and the same basis set of polarized triple-zeta quality. The main attention is paid to the impact of spatial topology and the number of substituted nitrogen atoms in the simplest polycyclic aromatic hydrocarbons and their N-heteroaromatic analogues with one and two nitrogen atoms, e.g. anthracene – acridine – phenazine and phenanthrene – 7,8-benzoquinoline – 1,10-phenanthroline, on relative energies and radiative properties of their lowest singlet and triplet <em>ππ</em>∗ and <em>nπ</em>∗ states as well as wavenumbers and intensities of vibrational transitions in the mid-frequency IR region. The estimated eigenvalues of the lowest singlet nπ* state in nitrogen-substituted polycyclic aromatic hydrocarbons are a valuable contribution to data available in a literature since they are usually unobserved if they are located above the lowest singlet ππ* state.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109646"},"PeriodicalIF":1.9,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996330","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":"Improving numerical stability of the separation of variables method for light scattering by spheroids with size parameters beyond 1000","authors":"Jiachen Ding ,&nbsp;Ping Yang","doi":"10.1016/j.jqsrt.2025.109644","DOIUrl":"10.1016/j.jqsrt.2025.109644","url":null,"abstract":"<div><div>This study analyzes the numerical instability associated with using the separation of variables method (SVM) to solve light scattering by spheroids. An accurate and numerically stable solution to the single-scattering properties of a spheroidal particle is obtained. The numerical instability causes inaccurate calculation of the scattered field expansion coefficients with even expansion degrees (<em>n</em>) at expansion order <em>m</em> = 0. Relying on a quantitative analysis using numerical linear algebra techniques, we find that this problem originates in the expression of the linear equation system used to solve the expansion coefficients. A pseudoinverse method is adopted to substantially improve the numerical stability of the expansion coefficient calculation. The new SVM improved by the pseudoinverse method can be used to accurately compute single-scattering properties of spheroidal particles with size parameters beyond 1000.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109644"},"PeriodicalIF":1.9,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144926056","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":"Towards an optical gas standard for ammonia measurements in air at ambient levels","authors":"Andrea Pogány ,&nbsp;Nils O.B. Lüttschwager ,&nbsp;Gourab Dutta Banik ,&nbsp;Stefan Persijn ,&nbsp;Ewoud J.J. de Boed ,&nbsp;Christophe Sutour ,&nbsp;Tatiana Macé ,&nbsp;Javis A. Nwaboh ,&nbsp;Olav Werhahn ,&nbsp;Volker Ebert","doi":"10.1016/j.jqsrt.2025.109643","DOIUrl":"10.1016/j.jqsrt.2025.109643","url":null,"abstract":"<div><div>We describe thorough metrological characterization of a cavity ring-down spectrometer, combined with proprietary spectral evaluation algorithm. Our measurements show good linearity, good accuracy and short response time of the instrument in the 50-400 nmol/mol amount fraction range. Our spectral evaluation algorithm enables decreasing the offset to 0.12 nmol/mol from the values around 0.6-0.9 nmol/mol reported using the built-in data evaluation of the commercial spectrometer. We have successfully eliminated cross-sensitivity by water vapor via an advanced spectral fitting approach using line parameters published in the HITRAN2020 database. Our spectrometer has been compared to a traceable reference gas standard and the results show that it is a good candidate to become an optical gas standard for ammonia amount fraction measurements under laboratory conditions.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109643"},"PeriodicalIF":1.9,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899423","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":"Relationship between two different approaches relating electromagnetic and scalar beam shape coefficients","authors":"Gérard Gouesbet ,&nbsp;Jianqi Shen ,&nbsp;Leonardo A. Ambrosio","doi":"10.1016/j.jqsrt.2025.109616","DOIUrl":"10.1016/j.jqsrt.2025.109616","url":null,"abstract":"<div><div>Two different approaches, with many different conventions, have been recently published to express electromagnetic beam shape coefficients, encoding the structure of laser beams, in terms of scalar (more specifically acoustical) beam shape coefficients. One approach, call it VP1, expresses the electromagnetic fields using one single vector potential, while the second approach, call it VP2, expresses the electromagnetic fields in terms of two vector potentials. In this paper, we discuss the relationships between the VP1 and VP2 approaches, showing how the vector potential of the VP1 approach is related to the vector potentials of the VP2 approach, and express the relationships relating the beam shape coefficients of one approach to the beam shape coefficients of the other.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109616"},"PeriodicalIF":1.9,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899424","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":"Absorption cross sections of CHF3 (HFC-23) in synthetic air at 296 K","authors":"K. Berezkin ,&nbsp;G. Li ,&nbsp;N.O.B. Lüttschwager ,&nbsp;M. Kim ,&nbsp;H. Bohlius ,&nbsp;V. Ebert ,&nbsp;J.J. Harrison ,&nbsp;A.V. Domanskaya","doi":"10.1016/j.jqsrt.2025.109642","DOIUrl":"10.1016/j.jqsrt.2025.109642","url":null,"abstract":"<div><div>We report high accuracy absorption cross sections of fluoroform (CHF₃) in synthetic air at 296 K. The measured FTIR spectra underwent extensive processing, yielding accurate integrated intensity values for seven ro-vibrational bands in the mid-infrared region. Integrated cross sections in the regions of the major fundamental bands <span><math><msub><mi>ν</mi><mn>3</mn></msub></math></span>, <span><math><msub><mi>ν</mi><mn>4</mn></msub></math></span> and <span><math><mrow><msub><mi>ν</mi><mn>2</mn></msub><mo>/</mo><msub><mi>ν</mi><mn>5</mn></msub></mrow></math></span> dyad have expanded uncertainties below 1.3 % (<em>k</em> = 2). Integrated cross sections in the region of combination bands <span><math><mrow><msub><mi>ν</mi><mn>2</mn></msub><mo>+</mo><msub><mi>ν</mi><mn>6</mn></msub></mrow></math></span> and <span><math><mrow><msub><mi>ν</mi><mn>2</mn></msub><mo>+</mo><msub><mi>ν</mi><mn>3</mn></msub></mrow></math></span> were determined with uncertainties less than 2 % (<em>k</em> = 2). Comparison of the integrals with values from the PNNL database showed consistency between both datasets. The influence of self-broadening effects of the spectral profiles, and the impact on the averaging procedures employed in the PNNL database and the current work are addressed. Experimental spectra and the corresponding composite spectra are available online in two archives: <span><span>doi:10.7795/720.20250709</span><svg><path></path></svg></span> (experimental cross sections) and <span><span>doi:10.7795/720.20250708</span><svg><path></path></svg></span> (composite spectra).</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109642"},"PeriodicalIF":1.9,"publicationDate":"2025-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899456","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":"Calculation of beam shape coefficients for elliptical Gaussian light using the scalar translational addition theorem","authors":"Haoyu Jiang,&nbsp;Yang Yang,&nbsp;Yiqian Tian,&nbsp;Yu Wang,&nbsp;Haitao Yu,&nbsp;Jianqi Shen","doi":"10.1016/j.jqsrt.2025.109641","DOIUrl":"10.1016/j.jqsrt.2025.109641","url":null,"abstract":"<div><div>A two-step indirect method for calculating the beam shape coefficients (BSCs) of the electromagnetic field of the circular Gaussian beam was recently presented, based on the spherical wave expansion of the scalar potential function and the scalar translational addition theorem (STAT). In this paper, the indirect method is extended to the shaped beam with non-axisymmetric cross-section, more specifically the elliptical Gaussian beam (EGB). Using the angular spectrum decomposition method, the BSCs of the scalar potential function are formulated in the beam coordinate system. Then, based on the STAT, the scalar BSCs in the particle coordinate system are obtained, which can be further transformed to the electromagnetic BSCs of the EGB. Numerical calculations are carried out to verify the accuracy and efficiency of the indirect method.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109641"},"PeriodicalIF":1.9,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899457","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":"Exploring light scattering as a streamlined approach to cell system evaluation","authors":"Mariia Naumenko ,&nbsp;Mikhail Panfilov ,&nbsp;Denis Polivtsev ,&nbsp;Petr Laktionov ,&nbsp;Sergey Kulemzin ,&nbsp;Alexander Moskalensky","doi":"10.1016/j.jqsrt.2025.109640","DOIUrl":"10.1016/j.jqsrt.2025.109640","url":null,"abstract":"<div><div>The characterization of disperse systems is a critical task across multiple industrial sectors, including biotechnology. Optical density (OD) measurements are frequently used to analyze turbid samples. However, it is not suitable for low-scattering media, such as for example mammalian cell cultures or samples for water quality assessment. In this study, we utilize the measurement of side scattering (90°) from several points along the light beam. This scheme includes highly sensitive light-scattering (nephelometry) principle and in the same time allows to evaluate light attenuation by turbid samples. Although theoretical description of the problem is quite complicated due to multiple scattering, we show that mutual dependence of measurements pertaining to different points obey certain mathematical relations. As a result, during the increase of particle concentration data points move along well-defined trajectory, whose shape is invariant and only the overall scale is controlled by optical parameters of the particles. This result is confirmed experimentally with systems having vastly different parameters including polystyrene beads, silica beads, milk fat globules, <em>E.coli</em> bacteria and mammalian cell lines. We also observed signs of trajectory alteration due the change of individual cells' optical parameters during culture growth. Our findings demonstrate that the described light scattering analysis enables monitoring of particle and cellular systems, highlighting its potential as a practical, adaptable, and cost-effective approach.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109640"},"PeriodicalIF":1.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899466","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":"The Umov effect in polydisperse dust aggregates","authors":"N.N. Devi ,&nbsp;H.S. Das ,&nbsp;A. Suklabaidya ,&nbsp;B. Goswami","doi":"10.1016/j.jqsrt.2025.109617","DOIUrl":"10.1016/j.jqsrt.2025.109617","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study explores the optical behavior of polydisperse dust aggregates, focusing on four structural types: ballistic cluster–cluster aggregates (BCCA), ballistic agglomeration (BA), and its variants with one (BAM1) and two migrations (BAM2). We analyze how the polarization maximum (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;max&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) and albedo (&lt;span&gt;&lt;math&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;) (both in logarithmic scale) vary with key scattering parameters such as the complex refractive index (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), cluster radius (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;–&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), and porosity (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;≈&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;64&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;99&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), assuming 1024 monomers per aggregate. The analysis incorporates silicate, organic refractory, and Halley-like dust compositions. The Umov effect – an inverse correlation between &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;max&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; – is evident when &lt;span&gt;&lt;math&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; is varied in the range &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;001&lt;/mn&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (with &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) across BA, BAM1, and BAM2 structures. In contrast, when porosity is varied across the range &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;≈&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;64&lt;/mn&gt;&lt;mtext&gt;–&lt;/mtext&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;87&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; for polydisperse aggregates of all three dust types, a linear inverse relationship between &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;max&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; is observed. BCCA aggregates generally do not follow the Umov effect due to small monomer size parameters, but for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;≥&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;643&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;45&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), the Umov effect is restored. When the size parameter (&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;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mi&gt;π&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) is varied, the Umov effect holds for BA (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;≈&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;87&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), BAM1 (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;≈&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;74&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), and BAM2 (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;≈&lt;/m","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109617"},"PeriodicalIF":1.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144901749","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 large particles – a refinement to the Mean-Field T-matrix method –","authors":"Robert Botet","doi":"10.1016/j.jqsrt.2025.109589","DOIUrl":"10.1016/j.jqsrt.2025.109589","url":null,"abstract":"<div><div>In the realm of light scattering computational techniques, the T-matrix method serves as a pivotal tool for analysing dust particles composed of aggregated spherical monomers. However, an inherent and significant limitation restricts its application to small aggregates due to the computational demands of processing the translation matrix, whose size becomes prohibitive for aggregates with a large number of spheres. The Mean-Field T-matrix method (MFTM) was proposed as an approximation to address this issue, enabling the treatment of arbitrarily large particles. In the present study, the MFTM method is extended to encompass dust particles that are large, irregular aggregates of polydisperse spherical monomers made from various materials. Additionally, a recently proposed accurate pair correlation function is integrated to describe the spatial distribution of monomers within the aggregate. These advancements render the refined MFTM method both efficient and capable of processing realistic, large dust aggregates. This paper presents a comprehensive application of the enhanced MFTM method to fractal aggregates of spheres with radii following a Schulz distribution. Notably, the refined method is expected to facilitate the derivation of optical properties of atmospheric aerosols and the interpretation of observations from protoplanetary disks.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"347 ","pages":"Article 109589"},"PeriodicalIF":1.9,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889236","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}