Journal of Quantitative Spectroscopy & Radiative Transfer最新文献

{"title":"Adaptive angular resolution for time-dependent radiative transfer simulations based on local radiation field anisotropy","authors":"Makito Abe ,&nbsp;Hidenobu Yajima ,&nbsp;Masayuki Umemura ,&nbsp;Yoko Hoshi","doi":"10.1016/j.jqsrt.2026.109820","DOIUrl":"10.1016/j.jqsrt.2026.109820","url":null,"abstract":"<div><div>Developing a fast and accurate radiative transfer calculation method is vital in modeling light propagation in biological tissues. We present a novel acceleration scheme for three-dimensional time-dependent radiative transfer simulation. In biological tissues, required angular resolutions for anisotropic radiation fields sensitively depend on spatial positions. Our new scheme changes the angular resolutions with the positions automatically based on local anisotropies of the radiation fields using the spherical Haar wavelet basis function. We apply the new code to simulations of light propagation in a box of polyurethane phantom mimicking biological tissue. We show that the new scheme achieves the acceleration of a factor of <span><math><mrow><mo>∼</mo><mn>8</mn></mrow></math></span> at most and <span><math><mrow><mo>∼</mo><mn>3</mn></mrow></math></span> on average compared to a simulation with the constant angular resolution while its accuracy keeps the same level. We find that the acceleration becomes more noticeable if low-angular resolution areas spread with time according as the diffuse radiation dominates. As the result of the fewer required angular bins, we find that the new code has the potential to reduce the memory use to <span><math><mrow><mo>∼</mo><mn>20</mn><mtext>%</mtext></mrow></math></span> at the maximum. Thus, our new scheme also has the advantage from the viewpoint of computational resources. We note that our new scheme is applicable not only to steady-state media but also to scenarios where the physical state of matter changes dynamically. Our new scheme will be a powerful tool to perform radiative transfer simulations of more than a thousand models which must be important in developing machine learning models.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"352 ","pages":"Article 109820"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956752","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":"Applicability of the Arago-Biot mixing formula to the effective refractive index of particle suspensions","authors":"Augusto García-Valenzuela,&nbsp;Nadia E. Álvarez-Chávez,&nbsp;Anays Acevedo-Barrera","doi":"10.1016/j.jqsrt.2025.109791","DOIUrl":"10.1016/j.jqsrt.2025.109791","url":null,"abstract":"<div><div>We study the applicability of the Arago-Biot mixing formula to calculate the effective refractive index of particle suspensions using the anomalous diffraction approximation, when the size of the particles is comparable to the wavelength of radiation. Interest in this mixing formula stems from the fact that it does not require knowledge of the particles' size or shape. Thus, it can be useful for determining the refractive index of particles in suspension of size comparable to the wavelength of radiation, regardless of their shape or size distribution. We present an analysis and graphs in the refractive-index-contrast versus size-parameter 2D space of the error of the Arago-Biot mixing formula and the error of using this mixing formula to infer the refractive index of particles in suspension. We consider non-absorbing and absorbing particles. The results obtained demonstrate the viability of inferring the refractive index of particles in suspension with accuracy in the second decimal place by reducing the refracting index contrast with the matrix medium for particles comparable to the wavelength of light.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"351 ","pages":"Article 109791"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145731366","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 scalar and electromagnetic beam shape coefficients for fields with a propagating factor of exp(±iβz): Linear and circular polarizations","authors":"Leonardo A. Ambrosio ,&nbsp;Luiz F.M. Votto ,&nbsp;Jianqi Shen ,&nbsp;Gérard Gouesbet ,&nbsp;Jiajie Wang","doi":"10.1016/j.jqsrt.2025.109789","DOIUrl":"10.1016/j.jqsrt.2025.109789","url":null,"abstract":"<div><div>In light and acoustic scattering, physical fields such as acoustic pressure and electromagnetic waves are expanded in partial waves, the expansion coefficients being known as the beam shape coefficients (BSCs). In acoustics, the BSCs are found from scalar fields, while in optics transverse magnetic and electric BSCs are calculated from the radial electric and magnetic field components, respectively. The relationship between acoustic and electromagnetic BSCs has been a recent active area of research. Previous works have focused on the assumption that such a relationship can be established by forcing the acoustic/scalar fields to be particular components of electromagnetic vector potentials. Here, we present an alternative approach in which the scalar fields are directly associated with a transverse electric field component. Such an analysis extends previous work and allows for a direct description of the electromagnetic BSCs of important optical fields from scalar waves. The analysis is restricted to solutions to the scalar Helmholtz equation which carry a propagating factor of the form <span><math><mrow><mo>exp</mo><mrow><mo>(</mo><mo>±</mo><mi>i</mi><mi>β</mi><mi>z</mi><mo>)</mo></mrow></mrow></math></span>, such a factor being the only one to carry any dependence on the axial coordinate. An example is provided for a specific class of structured, non-diffracting fields constructed from discrete superpositions of Bessel beams, known in the literature as <em>frozen waves</em>.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"351 ","pages":"Article 109789"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704974","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":"Learning to precondition: Reinforcement learning enhanced three-level circulant preconditioning for the Discrete Dipole Approximation","authors":"Steven Lanier","doi":"10.1016/j.jqsrt.2025.109741","DOIUrl":"10.1016/j.jqsrt.2025.109741","url":null,"abstract":"<div><div>Simulating light interaction with complex arbitrary geometry is crucial across the sciences. The Discrete Dipole Approximation (DDA) offers versatility for such problems but faces significant computational challenges, particularly for optically large or high-index systems, limiting its practical scope. Prior circulant preconditioning work, building on frameworks by Chan and Olkin and applied to DDA by Groth et al., demonstrated speedups primarily for quasi-2D geometries while attempts to create stable three-level preconditioners for general 3D structures were unsuccessful. Here we present an efficient and robust DDA implementation featuring a successful three-level circulant preconditioner stabilized through several key enhancements: optimized complex diagonal elements, controlled dimensional expansion and folding of the preconditioner structure, and automated parameter tuning via reinforcement learning. This preconditioning strategy is integrated with a custom GPU iterative solver incorporating stability improvements. Our approach effectively handles arbitrary 3D geometries, including non-homogeneous objects with varying refractive indices and multi-object scenarios with differing material values. The implementation yields substantial computational gains, often exceeding an order of magnitude reduction in iteration count or solution time, enabling convergence for more traditionally difficult problems and reducing demanding simulations from hours to minutes or even seconds on standard hardware. This work significantly extends the range of complex systems amenable to DDA modeling, facilitating advanced electromagnetic simulations relevant to nanophotonics, materials characterization, and atmospheric/biological optics.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"350 ","pages":"Article 109741"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145515579","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":"Forbidden lines in highly charged strontium-like ions","authors":"Zhaoying Chen ,&nbsp;Yuhang Ge ,&nbsp;Wenhao Xia ,&nbsp;Min Wang ,&nbsp;Liangyu Huang ,&nbsp;Yaming Zou ,&nbsp;Baoren Wei ,&nbsp;Xiang Gao ,&nbsp;Ke Yao","doi":"10.1016/j.jqsrt.2025.109795","DOIUrl":"10.1016/j.jqsrt.2025.109795","url":null,"abstract":"<div><div>Spectra of Sr-like Sn<span><math><msup><mrow></mrow><mrow><mn>12</mn><mo>+</mo></mrow></msup></math></span>, Xe<span><math><msup><mrow></mrow><mrow><mn>16</mn><mo>+</mo></mrow></msup></math></span>, La<span><math><msup><mrow></mrow><mrow><mn>19</mn><mo>+</mo></mrow></msup></math></span>, Pr<span><math><msup><mrow></mrow><mrow><mn>21</mn><mo>+</mo></mrow></msup></math></span>, Nd<span><math><msup><mrow></mrow><mrow><mn>22</mn><mo>+</mo></mrow></msup></math></span>, and Sm<span><math><msup><mrow></mrow><mrow><mn>24</mn><mo>+</mo></mrow></msup></math></span> ions in the wavelength range of 200–600 nm were measured using an electron beam ion trap. A total of thirty four magnetic dipole transition lines were identified with twenty four lines newly assigned. Theoretical calculations were performed using the multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction methods, incorporating the Breit interaction and the dominant quantum electrodynamics effects. The calculated results show good agreement with experiment, with an average deviation below 1.0%. The experimental spectra reported provide reliable reference data for further studies.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"351 ","pages":"Article 109795"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784688","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":"Model study of stationary quasi-homogeneous cesium-containing photoplasma","authors":"Sergey A. Astashkevich","doi":"10.1016/j.jqsrt.2025.109794","DOIUrl":"10.1016/j.jqsrt.2025.109794","url":null,"abstract":"<div><div>A model of a spatially homogenous stationary Cs-containing photoplasma far from optical saturation is developed for uniform spectral pumping within the D1 and D2 cesium line range. The plasma chemistry, radiation transfer, and ambipolar diffusion of charged particles are all explicitly considered. Unlike previous studies of sodium-containing photoplasmas, this work includes associative ionization at both resonance and non-resonance levels. Along with the penning and associative ionization processes, the first and second kind of electron collisions and stepwise ionization were considered. Radiation transfer is accounted for the Voigt profile for the resonance cesium lines in the Biberman-Holstein approximation, taking into account self-broadening and Van der Waals broadening of the lines by the buffer gas atoms. The electron density and temperature and densities of atomic and diatomic cesium ions were determined by solving a system of equations for the atomic level and ion densities as well as the electron energy balance. For example, parameters for pure Cs and Cs–Ar photoplasmas in a cylindrical cell were obtained over a wide range of resonance excitation rates and partial pressures of gas components. A comparison with previously obtained data for cesium and sodium photoplasmas was made. The results can be used to design photoelectric converters based on cesium-containing gas cells.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"351 ","pages":"Article 109794"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784689","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":"Helium-induced broadening and shifting in the first overtone of hydrogen fluoride","authors":"I.A. Tolstikov ,&nbsp;A.V. Domanskaya ,&nbsp;O.O. Diachkova ,&nbsp;R.E. Asfin","doi":"10.1016/j.jqsrt.2025.109787","DOIUrl":"10.1016/j.jqsrt.2025.109787","url":null,"abstract":"<div><div>Spectra of HF mixtures with helium were recorded at elevated pressures ranging from 1 to 11 atm at 297.8(2) K. The rovibrational lines in the first overtone band were fitted with Voigt and Rautian profiles. The broadening and shifting coefficients for 19 lines in the first overtone are reported. An estimate for the velocity changing shifting coefficients for 11 lines is obtained. To the best of our knowledge, most of the reported line parameters are novel. Herman–Wallis coefficients were determined from the line intensity distribution as well.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"351 ","pages":"Article 109787"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689299","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":"N2-broadening coefficients and their temperature exponents for ethylene lines: A semi-empirical approach for (exo)planetary studies","authors":"Sarah Clavier ,&nbsp;Michael Rey ,&nbsp;Jeanna Buldyreva","doi":"10.1016/j.jqsrt.2025.109758","DOIUrl":"10.1016/j.jqsrt.2025.109758","url":null,"abstract":"<div><div>Nitrogen-broadening coefficients for ethylene absorption lines in the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mn>7</mn></mrow></msub></math></span> band are computed theoretically to fill in the enormous gaps existing in available experimental data. A semi-empirical method relying on the Anderson theory is employed for this purpose, with the model parameters adjusted on some rare room-temperature measurements and used further for calculations in extended temperature ranges. The spectroscopically active molecule C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> is rigorously treated as an asymmetric top, and its energy levels and wavefunctions are accurately computed by a quantum-chemistry methodology based on <em>ab initio</em> potential energy surfaces. Theoretical broadening values are obtained for the temperature range 100–1000 K relevant to studies of planetary and exoplanetary atmospheres. These values are further analyzed by the traditional power law to get the associated temperature-dependence exponents. Comparisons of the computed theoretical results with previous measurements and calculations are provided at a low temperature of 173 K to validate the theoretical method chosen. Since the power law describes perfectly the considered temperature range, the sets of reference-temperature broadening coefficients and their temperature exponents can be safely used for higher temperatures where semi-classical approaches applicability only grows. These data are provided for the quantum numbers <span><math><mrow><mn>0</mn><mo>≤</mo><mi>J</mi><mo>≤</mo><mn>47</mn></mrow></math></span>, <span><math><mrow><mi>K</mi><mo>≤</mo><mn>26</mn></mrow></math></span> and the three <span><math><mi>P</mi></math></span>-, <span><math><mi>Q</mi></math></span>-, <span><math><mi>R</mi></math></span>-branches of the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mn>7</mn></mrow></msub></math></span> band, i.e. represent the most comprehensive up-to-date description of N<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-broadened ethylene linewidths suitable for integration into spectroscopic databases and high-temperature simulations of (exo)planetary atmospheres.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"350 ","pages":"Article 109758"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145559886","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":"Volumetric optical properties of alumina-carbon soot hybrid medium in high-speed aircraft plumes","authors":"JingYing Li,&nbsp;XiaoXiao Song,&nbsp;ShanShan Fan","doi":"10.1016/j.jqsrt.2026.109808","DOIUrl":"10.1016/j.jqsrt.2026.109808","url":null,"abstract":"<div><div>The spectral radiation characteristics of aircraft exhaust plumes are significantly influenced by the volumetric optical properties of alumina-carbon soot hybrid media. This study develops a dedicated computational algorithm to determine these properties by establishing realistic models for alumina and carbon soot clusters in the plume and derives formulas for calculating the volumetric optical properties per unit volume of the hybrid medium. The characteristics are analyzed in the ultraviolet (280<!--> <!-->nm) and infrared (4.3<!--> <!-->µm) bands. The results show that: (1) In the ultraviolet band, the extinction process is primarily governed by scattering from alumina particles, with carbon soot particles accounting for over 99% of the absorption. Conversely, in the infrared band, extinction is dominated by absorption from carbon soot particles, while the contribution of alumina particles to extinction is only 2%–4.5%. (2) In the ultraviolet band, the volumetric scattering phase function of the hybrid medium exhibits strong forward scattering, which decreases with increasing carbon soot content. In the infrared band, the scattering phase function becomes relatively flat, demonstrating isotropic scattering characteristics. (3) Regarding polarization properties, the volumetric linear polarization degree in the ultraviolet band is predominantly negative, and the circular polarization displays a distribution from strong right-handed in the forward direction to strong left-handed in the backward direction. In the infrared band, the linear polarization exhibits a strictly even-symmetric positive distribution about 90°, and the circular polarization shows strict central symmetry about 90°. The conclusions of this study provide a theoretical basis for multi-band radiation characteristic modeling and target identification of high-speed aircraft exhaust plumes.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"352 ","pages":"Article 109808"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928118","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":"Transmittance of Gaussian beam in anisotropic jet engine exhaust turbulence","authors":"Yahya Baykal","doi":"10.1016/j.jqsrt.2026.109816","DOIUrl":"10.1016/j.jqsrt.2026.109816","url":null,"abstract":"<div><div>Transmittance is a metric that provides information on how much of the intensity is transferred to the receiver for a given medium. One of the definitions of transmittance is the ratio of the average received intensity in the presence of turbulence to the received intensity in the absence of turbulence. Under such definition, transmittance is found in an anisotropic jet engine exhaust turbulent environment. For various receiver points, transmittances versus the wireless optical communication (WOC) link and anisotropic jet engine exhaust turbulence parameters are presented. The results are useful for designers of WOC links that are installed in the premises such as the airports that possess jet engine exhaust turbulence.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"352 ","pages":"Article 109816"},"PeriodicalIF":1.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956756","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}