A quasi-universality property of Mie scattering was reported in a recent publication by C.M. Sorensen [J. Quant. Spectrosc. Radiat. Transf. (2013) 131, 3]: the authors represent the forward scattered intensity, normalized by the differential Rayleigh cross section, as a function of the phase shift parameter. Here we provide clear experimental evidence of this result; the Sorensen plots are produced

Iodine has been an element of recent interest for commercial use as fuel in electrostatic propulsion systems. A lingering problem when investigating ionized iodine using non-perturbative, laser-based techniques is determining the spectral width, i.e., the species temperature, of iodine. To this end, the hyperfine structure must be well understood to develop a spatially resolved diagnostic technique

High-resolution quantum cascade laser absorption spectrum of cis-HONO of the v2 band has been recorded and analyzed, for the first time, in the mid-infrared region of 1659.2-1662.2 cm−1 (R-branch of the v2 band, N=O stretch). Positions and effective line intensities were determined for about 60 new lines. The absolute absorption frequencies were directly measured during spectral scan using a wavelength meter

Four spectra of methane in natural isotopic abundance in the 4100-4300 cm−1 region were recorded by using a Fourier transform spectrometer in Reims, France at long paths (202 m, 602 m, 1604 m and 1804 m) and different pressures. Additional spectra of 12CH4 covering the same region were obtained at 100-123 K for different pressures, 93 m path length at Synchrotron SOLEIL in Paris for different pressures

In this paper, the multireference configuration interaction method (MRCI) combined with the Davidson correction (+Q) is used to study the high-level ab initio calculation of AsO electronic states. The potential energy curves (PECs) of 27 Λ-S states and 18 Ω states related to the three lowest dissociation limits are obtained. According to these PECs, the spectroscopic constants of Λ-S and Ω states can

The Multiconfiguration Dirac-Hartree-Fock method is used to calculate energy levels, radiative rates and lifetimes for electric-dipole (E1), electric-quadrupole (E2), magnetic-dipole (M1), and magnetic-quadrupole (M2) transitions among the lowest 97 levels belonging to the 3s23p2, 3s3p3, 3s23p3d, 3s3p23d, 3s23d2, and 3p4 configurations in silicon-like Mo XXIX. High-accuracy calculations have been performed

Directional radiative intensity calculation is very useful for inverse analysis since it can provide abundant useful information inside radiative systems. In this work, spherical harmonics method (PN approximation) is utilized to calculate directional radiative intensity. Meanwhile, in order to improve the computational accuracy of radiative intensity, a method named PN-path integral method which is

The absorption spectrum of the 18O3 isotopologue of ozone was recorded by cavity-ring down spectroscopy between 7920 and 7985 cm−1 with a routine noise equivalent absorption, αmin, on the order of a few 10−11 cm−1. This permitted to detect and analyze an extremely weak vibrational band assigned as 7ν1+ν3 following predictions from the ab initio potential energy surface reported in J Chem Phys 2013;139:134307

Recent experiments on single and double ionization of atoms by Compton scattering potentially open the door to establishing new methods of dynamical spectroscopy complementing the well-known methods like (e,2e) and (e,3e) spectroscopy. In this paper we explore the possibility to use double ionization of the helium atom by Compton scattering as a tool for direct spectroscopy of electron-electron correlations

The Stark broadening of hydrogen lines with a low upper principal quantum number n is reexamined in the case of plasmas subject to a large (≳1 kT) external magnetic field. This investigation has been motivated by the observation of strong Zeeman splitting in a significant number of white dwarf spectra. The diamagnetic Zeeman effect term present in the Hamiltonian removes the degeneracy of the energy

The effects of polydispersity on radiative and interfacial convective heat transfer are investigated in particle–gas two-phase media for solar particle receiver applications. Non-grey radiative transfer is analysed using the collision-based Monte Carlo ray-tracing method. The Mie theory is employed to calculate radiative properties of particles. The finite volume method and the explicit Euler time

Solar thermophotovoltaic (STPV) technology has attracted much attention because its theoretical efficiency, which is much higher than the efficiency of the Shockley-Queisser limit. In this paper, conical multilayer cylinder metamaterial absorber is first proposed and a narrowband emitter matched with an InGaAsSb cell are designed for an STPV system. Considering the actual operating temperature of the

High resolution ro-vibrational spectroscopy of the A2Π1/2(v′ = 0) → X2Σ1/2(v = 0) band, for the buffer-gas-cooled magnesium monofluoride (25,26MgF) isotope molecules, has been measured by the in-cell direct absorption. Due to the decent populations in the low-lying rotational states (X2Σ1/2(v = 0, N = 0, 1)) for the cooled 25,26MgF molecules, the rotational levels and constants of the A2Π1/2(v′ = 0)

This study evaluates the effect of dependent scattering and particle overlapping on the integral radiation characteristics of fractal aggregates of monodisperse and non-absorbing spherical particles for a wide range of particle and aggregate sizes. It also aims to identify a scattering approximation capable of rapidly predicting these radiation characteristics. The scattering cross-section and asymmetry

Most of the exoplanets detected up to now transit in front of their host stars, allowing for the generation of transmission spectra; the study of exoplanet atmospheres relies heavily upon accurate analysis of these spectra. Recent discoveries mean that the study of atmospheric signals from low-mass, temperate worlds are becoming increasingly common. The observed transit depth in these planets is small

Dual autofocusing circular Airy beams (CAB) are proposed by introducing two different initial launch angles into the phase of light fields. Appropriate values of two launch angle parameters are chosen to enhance dual focusing property and reduce the interference effect. The relation between this dual autofocusing property and corresponding parameters are investigated. Our theoretical results show that

This work studies the optical binding of a dimer composed by dielectric particles close to a graphene sheet. Using a rigorous electromagnetic method, we calculated the optical force acting on each nanoparticle. In addition, we deduced analytical expressions enabling to evaluate the contribution of graphene surface plasmons (GSPs) to optical binding. Our results show that surface plasmon on graphene

A narrow band model (NBM) with the absorption coefficient as the fundamental radiative property is investigated so that numerical solution methods compatible with the differential form of the radiative transfer equation (RTE) may be employed. The advantage of a NBM based on the absorption coefficient rather than the transmissivity is that the expression for the mean absorption coefficient is independent

A set of surface integral equations (SIEs) of Fredholm equations of the second kinds is used to study 3D light-matter interaction at the nanoscale, particularly for the plasmonic effect. Based on this method, we find that the streamline of Poynting vector (energy flux) winds along the long axis of a gold nanocuboid as irradiated by a circularly polarized light propagating in the short-axis direction;

We study a nonlinear selective reflection from an interface YAG/high density vapor of the natural mixture of Rb isotopes at the components of 5S1/2−5P3/2 transition. The Doppler width is small by compare with the dipole-dipole interactions induced width of 6.1 GHz. In the experiment a cw laser beam with a variable intensity is used. There are two main contributions to the effective spectral linewidth:

In the present study, a two-step machine learning approach is proposed and tested based on the Greenhouse gases Observing SATllite (GOSAT) spectral measurements to efficiently retrieve the atmospheric CO2 column density. A simple one-dimensional line-by-line forward radiation model is developed to simulate the GOSAT observed spectra, which is used to generate the training data for the two-step machine

Simulating the magnetic field interactions with plasmas plays a paramount role in astrophysics, having significant impacts in several topics. Here, we propose a novel computational method within the framework of relativistic theory to the determination of the atomic structures and radiative properties of atoms or ions in presence of the dense and solid density magnetized plasma environments. In the

This paper describes a detailed theoretical analysis of the ionization lineshape based on numerical integration of coupled differential equations of motion for an optical double-resonance (ODR) ionization scheme. The results of the optimization studies, to identify laser intensities of both the excitation steps for efficient and selective ionization of 168Yb isotope are presented. The evaluated saturation

In this study, we examine the energy density distribution inside laterally infinitely extended turbid slabs due to perpendicular and oblique plane illumination with monochromatic light. We solve the scalar radiative transfer equation analytically for the fluence rate inside a slab to obtain the normalized energy density and compare it to the average energy density resulting from full vectorial numerical

Research on the radiative properties of porous fly ash particles is highly important for accurately assessing the radiative impact of particles and their remote-sensing measurements. We develop a general porous particle model based on the particle superposition model for flexibly constructing variations in the particle shape, size parameters, porosity, pore size, and pore dispersed distribution. Concentrated

As to study the scattering characteristics of millimeter wave by sand particles, the integrated detection on dust storms over the Taklimakan Desert was the first time to conduct with the Ka band millimeter wave radar, the Grimm 180, the Laser Particle Size Analyzer and the visibility meter. The complex permittivity of sand particle (εm), the probability distribution function of sand particles, the

High-resolution time-resolved Raman spectroscopy of laser-shocked liquid carbon disulfide (CS2) is reported. The symmetric stretching mode (ν1) and first overtone of the bending mode (2 ν2) of CS2 at 656 cm−1 and 802 cm−1 wavenumbers respectively are analyzed to monitor the possible phase transitions occurring in the sample during shock wave propagation in the pressure range 0.4 – 4.4 GPa by varying

The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required

Core-shell bimetallic particles are of great interest, since their plasmonic properties can differ significantly from the properties of their constituent components. In chemistry, they are widely used to improve various photovoltaic energy conversion processes, because they have good absorption and heat transfer properties. In this paper, the generalized non-local optical response theory is used in

Two spectrometers with complementary capabilities, in particular, a spectrometer with radioacoustic detection of absorption and a conventional video spectrometer, were used for systematic measurement of the frequencies of all magnetic-dipole transitions of the fine structure of the 16O16O molecule in the ground state X 3Σg− up to rotational states with N = 43. The obtained data set made it possible

The generalized oscillator strengths of the valence-shell excitations from the ground state to the 2p5(3s, 3s′, 3p, 3p′, 4s, 4s′) states of atomic neon have been determined by means of fast electron scattering, with an incident electron energy of 1500 eV and an energy resolution of about 80 meV. The adopted relative flow technique improved accuracy of the experimental measurements prominently. The

We present a semi-empirical parametrization method for calculation of spontaneous radiative decay rates of forbidden transitions on an example of analysis of experimental data for Sc II. The values of transition probabilities and radiative lifetimes of metastable levels are in perfect agreement with experimental ones. The obtained results are compared with other calculated data available. The predicted

The choice of gray gas absorption coefficient in the Rank Correlated Spectral Line Weighted-sum-of-gray-gases (RC-SLW) model is investigated. Several options are considered for calculating the gray gas absorption cross-section from the bounding supplemental absorption cross-sections, including that determined by inversion of the F-variable using Gauss Quadratures, the Geometric Mean of the bounding

In this work, we report quantitative absorbance measurements of nitric oxide (NO) diluted in nitrogen between 1700 to 2000 cm−1 and present three line mixing modeling approaches for the measured spectra. Static cell measurements were taken using a narrow-linewidth, external-cavity quantum-cascade laser at temperatures of 293 K and 802 K and pressures of 20–34 atm. The measured results exhibit considerable

We employ a neural network approach to classify aerosolised spherical particles according to both constituent material and size. The classification is based on simulated light scattered intensities in order to emulate the data obtained from an optical particle counter. Detection configurations of varying complexity, involving up to three wavelengths,forward- and backward-scattering detection and two

We improved the Wentzel-Kramers-Brillouin (WKB) approximation for calculating the electric field inside a scatterer. The new method, named WKBr, additionally takes into account refraction (rotation) of the incident rays at the particle-medium interface. For large particles the WKBr is equivalent to the geometric optics in the limit of relative refractive index m approaching 1. Thus, the resulting accuracy

We present the first report of optical absorption spectroscopy of H36Cl, a radioactive isotopologue of hydrogen chloride. We used Fourier-transform infrared spectroscopy to determine the line center wavenumbers of the fundamental rovibrational band lines P(10)–R(10) and the first overtone band lines P(1)–R(7) with total uncertainty of less than 0.0018 cm−1 (60 MHz) and 0.007 cm−1 (0.2 GHz), respectively

In characterizing droplets, the rainbow reveals information about the size of individual drops, their refractive index, temperature, and in some instances composition. Previous experience in exploiting rainbow scattering for this purpose has led to classical rainbow refractometry, but also to the global rainbow technique. To improve on these existing techniques, a highly focused Gaussian illumination

In this work, the effects of thermochemical non-uniformity on line-of-sight (LOS) laser absorption thermometry in counterflow diffusion flame (CDF) was systematically investigated. Differences between the LOS-determined temperature and the true core flame temperature was quantified considering the coupled effects of thermal and gas concentration non-uniformities along the LOS. Experimentally validated

Experimental measurement and analysis of the laser-induced frequency shifts (LIFSs) of photoassociation (PA) spectra in a spinor Bose–Einstein condensate (BEC) of sodium is reported. The trap loss spectra of the atoms in the BEC were recorded at different PA laser intensities. Linear variations of the frequency shift for different spin components were demonstrated. The analogous linear dependence on

Spatially and temporally resolved information on thermochemical conditions in hydrocarbon/air flames requires concentration and temperature data obtained by spontaneous Raman/Rayleigh scattering. During the combustion of renewable and more complex fuels, such as ethanol, partially oxidized hydrocarbons are created as intermediates in concentrations large enough to have an influence on the turbulence-chemistry

A differential absorption lidar (DIAL) for measurement of atmospheric nitrogen dioxide (NO2) concentration is developed based on atmospheric backscattered signals. Two Nd:YAG lasers are used to pump into two dye lasers to produce two wavelengths λon (448.1 nm) and λoff (446.6 nm), respectively. The NO2 absorption cross section varies with the change of ambient temperature. The changes of NO2 absorption

The Spectral Physics Environment for Advanced Remote Sensing (SPEARS) application programming interface (API) is a Python-based, line-by-line, local thermal equilibrium (LTE) spectral modeling code which is optimized for simultaneously synthesizing optical spectra from any combination of fundamental spectroscopic databases. In this article, we contribute two novel spectral modeling techniques to the

The discovery of 22 new energy levels of the La atom, having odd parity, is reported. These levels were derived from an analysis of unclassified spectral lines found either in optogalvanic spectra and/or Fourier transform spectra. The reliability of results obtained from the combination principle of Ritz was verified by hyperfine structure investigations. Further three new odd-parity levels of the

Four absorption bands of the jet-cooled molybdenum monoxide (MoO) molecule involving seven natural Mo isotopes have been investigated using laser induced fluorescence spectroscopy. All bands have large isotope shifts in rotational resolution, and are assigned to the transitions from the ground X 5Π−1 (v′′ = 0) state to the upper [14.11]2, [14.15]2, [14.24]2 and [15.04]2 states, respectively. The accurate

The nature of the water vapour continuum has been of great scientific interest for more than 60 years. Here, water vapour self-continuum absorption spectra are retrieved at temperatures of 398 K and 431 K and at vapour pressures from 1000 to 4155 mbar in the 8800 and 10,600 cm−1 absorption bands using high-resolution FTS measurements. For the observed conditions, the MT_CKD-3.2 model underestimates

Advanced high strength steel (AHSS) alloys derive their mechanical performance through a carefully controlled intercritical annealing process. Unfortunately, variations in spectral emissivity caused by selective oxidation and non-uniform surface roughness imparted by cold-rolling impact the accuracy of the pyrometrically-inferred temperatures used for process control. This study evaluates the spectral

The frequent occurrence of haze episodes in China poses a severe threat to human health. During the haze period, nitrate and mineral dust form a complex mixing state through heterogeneous reactions. The existing numerical models usually assume sulfate instead of nitrate in simulating the optical properties of aerosol, and the radiation difference between sulfate and nitrate needs to be evaluated. Therefore

We develop a new three-dimensional time-dependent radiative transfer code, TRINITY (Time-dependent Radiative transfer In Near-Infrared TomographY), for in-vivo diffuse optical tomography (DOT). The simulation code is based on the design of long radiation rays connecting boundaries of a computational domain, which allows us to calculate light propagation with little numerical diffusion. We parallelize

New 125I atomic decay emission data of medical interest are presented. The calculations are based on two atomic structure codes that implement the multi-configuration Dirac-Hartree-Fock method. Radiative and non-radiative ransition rates are calculated in this method and then used to generate the atomic deexcitation cascade. Subshell transition rates, level widths and fluorescence yields are compared

A cloud tomographic retrieval algorithm relying on (i) the spherical harmonics discrete ordinate method for computing the radiative transfer and (ii) the surrogate minimization method for solving the inverse problem has been designed. The retrieval algorithm uses regularization, accelerated projected gradient methods, and two types of surrogate functions. The performances of the retrieval algorithm

Temperature-dependence exponents of the traditional power law relating line-broadening coefficients at experimental and reference temperatures are deduced for CH3I-N2 lines in the ν6 band from theoretical estimates in the temperature interval 200–400 K recommended for HITRAN. Perfectly linear fits in log-log coordinates indicate that this simple law is sufficient and more advanced models such as the