A Surface Integral Equation (SIE) method has been implemented to analyze light scattering by arbitrarily shaped solid dielectric particles. Specifically, the Poggio–Miller–Chang–Harrington–Wu–Tsai formulation is discretized using the Galerkin method, employing Rao–Wilton–Glisson basis functions. The numerical solution is further accelerated through the application of the high-frequency Multilevel Fast

In this paper, the range of low-frequency microwave radar going through sand storms is numerically investigated with considering the attenuation and backscattering of charged sand grains along the link. It was found that strong sandstorms can reduce the range of microwave radar, which is reduced by < 5 % for radars at the L and S bands when the visibility is larger than 50 m; while with the visibility

High accurate ro-vibrational spectra of 12CD4 were measured in the pentad region with a Bruker IFS125 HR Fourier transform infrared (IR) spectrometer at an optical resolution of 0.003 cm−1 and different pressures and optical path-lengths. The analysis of 1264 experimental absolute transition strengths belonging to all nine ro-vibrational sub-bands of the 12CD4 pentad was performed using the Voigt profile

Absorption cross-sections at room temperature have been derived for two non-cyclic organic molecules cyanopropyne (CH3C3N) and isobutyronitrile (i-C3H7CN), and have been proposed for the 2024 update of the high-resolution transmission molecular absorption database (HITRAN). The gas phase infrared spectra of pure cyanopropyne and isobutyronitrile have been recorded at room temperature between 160 and

It has been recently demonstrated that the electromagnetic beam shape coefficients gn,Xm (X=TM or TE) which encode the structure of structured light beams may be expressed in terms of scalar, more specifically acoustical, beam shape coefficients. Because the technique used to obtain the relevant expressions relied on the properties of what is known as the finite series method, the aforementioned expressions

Here, we propose a graded hybridization strategy for the enhancement of radiative heat transfer, which is based on the heterostructure consisting of multilayer graded SiO2 gratings and black phosphorus (BP). In the near-field region, this graded hybridization strategy exhibits an advantage in radiative heat transfer capabilities when compared with conventional multiple surface plasmon polaritons (SPPs)

The spectrum of the Cd+6 ion excited in a vacuum spark and recorded with high resolution was studied in the range 170–320 Å. About 390 spectral lines of the 4p64d6 − (4p64d55p + 4p64d54f + 4p54d7) transitions were identified for the first time. All but one energy levels of the ground term configuration 4p64d6 were established. It also resulted in the determination of 171 and 36 levels of the 4p64d55p

16O12C17O is the fourth most abundant isotopologue of carbon dioxide. As part of this study, a total of 16223 rovibrational transitions, 9822 unique ones, measured for the ground electronic state of CO2, were collected from 31 articles, corresponding to the limited wavenumber range of 634–12727 cm−1. The measured transitions span the polyads P=0−17, where P=2v1+v2+3v3, and v1, v2, and v3 are the normal-mode

The atmospheric radiative transfer simulator ARTS is a software for computing atmospheric absorption, scattering, the transfer of radiation through an atmosphere, and sensor characteristics. It is written in C++ and can simulate remote sensing observations and radiative energy fluxes. The article describes version 2.6 of the software. There are numerous changes compared to the last ARTS publication

In this paper, we present libraries of simulated Raman spectra of di- and triatomic gaseous species relevant for reactive flows in high-temperature environments such as flames, ranging from 1 to 2500 K. The libraries encompass the most abundant isotopologues for key species, including CO ▪ . Simulation methodologies and results were primarily drawn from and validated in previous studies, with additional

A study of vibrational excitations of the OCS molecule in the framework of a polyad conserving local algebraic model is presented. The description starts establishing the Hamiltonian in configuration space in terms of normal modes and later on translated into an algebraic representation by introducing the bosonic realization for harmonic oscillator. Then a canonical transformation to local operators

Nitrous oxide is a long-lived greenhouse gas. Its isotopic composition provides valuable insights into sources and sinks, and about the mechanisms of formation. A major challenge in the spectroscopic analysis of the isotopocule compositions is the availability of accurate spectroscopic parameters, particularly for the minor 15N isotopocules. In this work, we introduce high-resolution spectroscopic

The new room temperature 12C16O2 line list (CDSD-2024-PI) is presented. This semi empirical line list contains the calculated line parameters (positions, intensities, air- and self-broadened half-widths, exponents of temperature dependence of air-broadened half-widths, and air pressure induced shifts). The reference temperature is 296 K, and intensity cutoff is 10-30 cm-1/(molecule cm-2). More than

We use a dual electro-optic comb system (EOOFC) and a differential chirped-pulse down conversion technique to study the R(6) manifold of the 2ν3 band (1645 nm) of methane at low pressure (< 1 kPa). In the frequency domain, the EOOFC method magnifies of the temporal dynamics of the system and due to of the 6-component asymmetric line shape, is shown to give unique amplitude and phase spectra that depend

In hot and dense plasma of solar and stellar interiors, Coulomb potentials between the nucleus and electrons are screened due to the complicated many-body interactions, resulting in significant alterations in atomic structures and dynamic properties of the embedded ions as well as the macroscopic transport properties, such as opacities. Here, the photoionization dynamics of the n ≤ 2 states of hydrogen-like

Nighttime light pollution is gaining significant interest in the scientific community and the public due to its harmful effects on human health, ecosystems, and leisure activities. Recently, many countries worldwide have been retrofitting their streetlights with light emitting diodes (LEDs) to enable smart street lighting while reducing energy use for street lights. However, little is known about the

Accurate emissivity measurement is essential for characterizing metasurfaces with highly directional thermal radiation. Traditional Fourier-transform infrared (FTIR) spectroscopy, particularly when using focusing optics, introduces measurement artifacts due to divergence angle effects, leading to underestimated emissivity and angular deviations. This study investigates the use of FTIR-based infrared

This study presents a novel methodology for retrieving the temporal evolution of a single physical parameter throughout the course of measurements conducted with imaging-FTIR systems. Rather than operating in the spectral domain, the proposed approach performs parameter fitting directly in the interferogram (i.e., the time or Optical Path Difference (OPD) domain). The method is based on a linearization

Atmospheric sounding from a space instrument usually leads to solving some inverse problem to retrieve a vertical number density profile of a particular constituent like ozone. The paper starts to consider the total number of calls to the forward model that are necessary to iteratively process a large ensemble of observations. For a comparable computational effort, it can be useful to generate a large

This paper presents the design, validation, and application of a new optically accessible gas cell capable of supporting high-pressure and high-temperature environments. The new cell enabled spectroscopic studies to be performed at pressures up to 200 atm and temperatures up to 1300 K. The cell was manufactured from a nickel alloy material to allow for high-temperature operation. Long sapphire rods

Polarization imaging has drawn significant attention from the research fraternity for decades due to its prominent imaging capabilities across multidisciplinary fields. Polarization imaging is based on the study of vectorial properties of light and associated vectorial transformations resulting from light-matter interaction. The range of polarization imaging and its applications is so broad that it

The high levels of nocturnal artificial light emissions from urban areas induce adverse effects on the environment and human health. Having adequate monitoring provides information for planning public policies and measuring their degree of achievement. Consequently, there is a need for optimal designing or redesigning of Light-Pollution Monitoring Networks focused on sensing the most impacting regions

This study quantifies the shortwave (SW) direct radiative forcing and heating rates associated with the monsoonal aerosol enhancements in the upper troposphere and lower stratosphere (UTLS) over a broad spatial domain (25°N to 37.5°N and 40°E to 95°E) within the Asian summer monsoon anticyclone (ASMA) region. Using satellites and reanalysis data, we examine three dominant aerosol scenarios—sulfate

HFC-23 (CHF3) retrievals from the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) have been improved. The volume mixing ratio (VMR) values in the recent update (v6) have increased compared to the previous ACE version 5.2 retrievals, and the relative uncertainties have decreased. The HFC-23 VMR time series has been calculated and compared with Advanced Global Atmospheric Gases

In this work, we calculate the Landé g-factors for the 1s22s22p1/2 and 1s22s22p3/2 states in B-like systems with nuclear charges Z ranging from 10 to 20. Our method starts with the Dirac–Coulomb–Breit Hamiltonian, incorporating electron correlation effects from both negative-energy and positive-energy states using third-order many-body perturbation theory, and including leading-order quantum electrodynamics

A ro-vibrationally resolved corona model for the molecular hydrogen Fulcher-α transition based on the Yacora solver is introduced. The model couples 1365 ro-vibrational levels of the X1Σg+, d3Πu and a3Σg+ states via electron impact excitation from the ground state into the d3Πu state and subsequent spontaneous emission into the a3Σg+ state. For the process of electron impact excitation a set of 45260

Accurate rotation-vibration (ro-vibrational) energy levels of the main isotopologue of ozone (16O3) in its ground electronic X̃1A1 state are determined by performing MARVEL (Measured Active Rotation Vibration Energy Levels) analysis on measured line positions from 29 sources of data published in scientific literature. A total of 50276 ro-vibrational transitions are considered yielding 13664 MARVEL

We report high-quality IR line lists of carbonyl sulfide (OCS) computed using an ab initio potential energy surface (PES) refined with selected energy levels from HITRAN2020 and experimental energies for highly excited vibrational states, and CCSD(T)/aug-cc-pV(T/Q/5+d)Z dipole moment surfaces (DMS). With PES accuracy σrms < 0.01 cm-1 for 16O12C32S levels and DMS fitting σrms = 1.3×10–7 au for potential

We discuss the electromagnetic scattering and radiation problems of multilayered spheres, reviewing the history of the Lorentz–Mie theory and the numerical stability issues encountered in handling multilayered spheres. By combining recursive methods with the transfer matrix method, we propose a modified transfer matrix algorithm designed for the stable and efficient calculation of electromagnetic scattering

The infrared spectra of 28SiH4 were measured at varied experimental conditions with a Bruker Fourier transform infrared spectrometer IFS125HR and analyzed in the 2800–3400 cm−1 region where eight sub-bands of the four stretching–bending bands of the octad are located. The 5670 transitions (Jmax=27) belonging to these sub-bands were assigned (which is 5.5 times higher in comparison with the amount of

Principal component analysis (PCA) is a linear mathematical transformation that reduces data dimensionality and enables easy identification of data variability; PCA converts a correlated mean-subtracted data set into a series of principal components (PCs). PCA can be performed on inherent optical properties to enhance the computational efficiency of radiative transfer calculations. Prior work has demonstrated

Photovoltaic (PV) solar farms, composed of arrays of photovoltaic panels, play a vital role in our effort to reduce the reliance on fossil fuels and mitigate global warming. Meanwhile, these panels alter surface radiative properties and can affect the local surface energy budget. To assess the influence of PV solar farms on the climate, previous modeling studies simply assumed flat solar panels lying

The relative intensities and cross sections of L-shell X-ray fluorescence (XRF) for elements with atomic numbers 64≤Z≤83 and compounds containing some of these targeted elements were measured at two excitation energies, 21 keV and 25 keV, using a synchrotron radiation source at XSAFS/XRF beamline of the Synchrotron Light Center for Experimental Science and Applications in the Middle East (SESAME),

Accurate intensities of the O2 A-band [b1Σg+←X3Σg−(0,0)] centered about 760 nm are essential to reduce biases in satellite- and ground-based remote measurements of column-integrated air mass and greenhouse gas concentration. In support of these remote sensing techniques, we made cavity ring-down spectroscopy measurements of 16O2 A-band line intensities up to J = 40, and we extrapolated these values

Oceanic particles play a significant role in determining the optical properties of the upper layer of oceans and, subsequently, the radiative forcing effect at the atmosphere-ocean interface. However, it is challenging to quantify the optical effects of these particles accurately. This study introduces a comprehensive optical property lookup table for oceanic particles, which can be used for oceanic

The intensities of all rovibrational electric quadrupole absorption lines in 16O2 (X3Σg−), for which the vibrational quantum number is v≤35 and the total angular momentum quantum number is J≤40, are calculated in the intermediate coupling using a new ab initio quadrupole moment curve of the ground electronic state of O2. The calculated values agree with those available in the HITRAN database, which

A laser absorption spectroscopy method was developed for in situ extraterrestrial sensing of four distinct water isotopologues near 2.64μm. Infrared rovibrational transitions for H216O, H218O, H217O, and HDO were selected within the overlapping ν1 and ν3 fundamental bands to maximize relative absorption intensity and reduce spectral interference with neighboring water lines and other species, such

Multispectral compatible stealth technologies are critically important in complex warfare environments, as they can effectively deceive various types of detection equipment, including visible light cameras and infrared thermal imagers. However, the integration of multiple stealth functionalities entails increasingly complex design requirements, posing significant challenges to the design of multispectral

The energy levels, transition probabilities, the relative uncertainty u, and wavelengths of electric dipole (E1) transitions for Ga-like Ag, Cd, and In ions were produced using the general purpose relativistic atomic structure package (GRASP2K) based on the fully relativistic multi-configuration Dirac-Hartree-Fock (MCDHF) method. The calculated energy levels and wavelengths are in excellent agreement

In this study, empirical and semi-empirical X-ray fluorescence cross-sections are generated for Kα1, Kα2, Kβ1′,and Kβ2′lines. The approach used was the fitting of experimental data by three-dimensional formulae. The empirical values were obtained through a fitting method making use of a three-dimensional function against atomic number Z and excitation energy E, resulting in a three-dimensional plot

Line shape of the first rotational transition of the CO molecule perturbed by N2 collisions was studied beyond the traditional Voigt profile at pressures from 0.1 up to 1500 Torr and temperatures from 238 up to 353 K using two different spectrometers with complementary abilities. Line intensity, shifting, mixing, broadening, and underlying continuum coefficients were retrieved. The experimental speed

A scattering model based on the Monte Carlo method (MCM) is developed to investigate the light scattering and extinction characteristics of non-aligned laser beams incident on a high concentration of mixed particle system. A set of measurement test systems for acquiring the scattered light energy distribution is constructed to verify the model accuracy, which yields the maximum root mean square errors

The CRTM transmittance coefficient generation package is a high-performance computing workflow to generate spectral and transmittance coefficients for the JCSDA Community Radiative Transfer Model (CRTM), which is used as an observation operator in satellite data assimilation applications. The characteristics of new instruments, whose observations are modeled by the CRTM, are encapsulated in these aforementioned

The high resolution submillimeter wave spectrum of the 12CH235Cl2 methylene chloride was analyzed in the wide spectral region from 0.075 up to 1.090 THz. The 5451 lines with the maximum values of quantum number Jmax=98 and Kamax=24, which correspond to 4037 unresolved singlet and central lines of triplets and 1414 peripheral lines of triplets (this spectroscopic structure is due to partially resolved/unresolved

In this work a preliminary feasibility study of the possibilities of laser cooling for the terbium atom was performed. Possible first- and second-stage cooling transitions were considered. For each of them semi-empirical estimation of the branching ratios and the lifetimes of the upper levels was performed. These should be regarded as rough estimates only, and certainly require experimental verification

The radiance of nighttime artificial lights measured by the VIIRS-DNB instrument on board the satellite Suomi-NPP increases at an average rate ∼2.2 %/yr worldwide, whereas the artificial radiance of the night sky deduced from the Globe at Night (GAN) unaided-eye observations of the number of visible stars is reported to increase at an average rate ∼9.6 %/yr. The difference between these two estimates

The hyperfine structure constants of the 1s22s22p2P1/2 and 2P3/2 states in the boron-like isoelectronic sequence with nuclear charges Z = 6 to 36 were calculated using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. In these calculations, we included electron correlation, Breit interaction, and one-electron quantum electrodynamics (QED) corrections. It was found that taking into account the

The congested absorption spectrum of ethylene (C2H4) is analyzed in the 2912-3270 cm-1 region dominated by the strong ν9 and ν11 CH stretching bands. A list of about 6870 lines has been retrieved from a room temperature Fourier transform spectrum (P = 2.568 hPa, L = 19.7 cm). Relying on the position and intensity agreements with a line list of 12C2H4 transitions calculated by the variational method

Estimating Top-of-Atmosphere (TOA) flux and radiance is essential for understanding Earth's radiation budget and climate dynamics. This study utilized polar nephelometer measurements of aerosol scattering coefficients at 17 angles (9–170°), enabling the experimental determination of aerosol phase functions and the calculation of Legendre moments. These moments were then used to estimate TOA flux and

The attenuation of electromagnetic waves due to rainfall is a critical factor in radar and telecommunication systems, particularly in frequency bands above 10 GHz, which is increasingly utilised for data transfer. This study addresses the gaps in understanding how these attenuation effects vary across different rainfall intensities and Drop Size Distributions (DSD). By analytically investigating the

Aerosols are an important factor leading to reduced visibility. In order to better comprehend the connection between visibility and aerosols, aerosol optical depth (AOD) and Angström exponent (AE) data from the Himawari-8 Advanced Himawari Imager (AHI) are used for validation in comparison with the data from the Aerosol Robotic Network (AERONET) observations in this paper, which amounted to 69,026

The scattering phase function of atmospheric particle usually has a strong forward peak due to the diffraction effect so that the scattering energy spans large order differences of magnitude in all scattering directions. Correspondingly, the accurate computation of multiple scattering processes in the radiative transfer is high resolution required and time-consuming. A decomposition method is described

He-collision-induced line-shape parameters of CO2 lines were measured in the ν3 band using Fourier transform spectra recorded at room temperature and with pressures ranging from 263 mbar to 1106 mbar. The measured transmission spectra were analyzed with the Voigt profile combined with the first-order line-mixing approximation, accounting for the instrument line-shape function. The He-broadening coefficients

The spectroscopic investigations on 3p32D5/2−2D3/2 transitions of phosphorus-like Ge17+, As18+, Se19+, Br20+, and Kr21+ ions at an electron beam ion trap were presented. The direct wavelength measurements were reported for the first time for Ge17+−Br20+ ions. All the measurements reached precision levels of a few ppm. The theoretical calculations were carried out using multi-configuration Dirac–Hartree–Fock

We present two new open-source codes, in the C language, for simulation of the line-by-line molecular (gas) absorption in the solar spectral region with wavelengths up to ∼2500 (nm). The first one, gcell, simulates absorption spectroscopy in a gas cell for a given length of the cell, temperature, and pressure. The second one, aspect, is for spectroscopy in Earth's atmosphere - a common need for remote

Using extensive numerical computations for several benchmark geometries, we demonstrate the physical correctness and numerical stability of a two-step algorithm for computing the electromagnetic-scattering T-matrix of homogeneous penetrable three-dimensional scatterers with smooth boundaries. Our numerical results show that the T-matrices computed with our algorithm have high accuracy, even at size

Emission of electrons and photons during the cascade decay of inner-shell vacancies created after the decay of unstable 125I radionuclide is simulated by construction and analysis of the cascade decay trees in isolated-ion approximation. The yields of final cascade ions, the number of emitted electrons and photons, and their spectra, are calculated. During one transformation of 125I, the total energy