The infrared spectra of SiD4 in natural abundance were measured in the region of 350 – 2050 cm−1 with a Bruker IFS 125HR Fourier transform interferometer at an optical resolution of 0.0021 and 0.0016 cm−1 and analyzed. Not less than 6490 transitions with Jmax = 33 were assigned for the first time to the bands 2ν4, ν2+ν4, and 2ν2 of the 28SiD4 molecule. Numerous ”hot“ dyad–pentad transitions (in general

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

SMUTHI is a python package for the efficient and accurate simulation of electromagnetic scattering by one or multiple wavelength-scale objects in a planarly layered medium. The software combines the T-matrix method for individual particle scattering with the scattering matrix formalism for the propagation of the electromagnetic field through the planar interfaces. In this article, we briefly introduce

The properties of light reflected from snow and ice surfaces are important for the understanding of light scattering theory and the interpretation of remote sensing in the cryosphere. Spectral measurements of the degree of linear polarization (DoLP) and its related Stokes parameters Pq=−Q/I and Pu=U/I of Stokes vector IS=[IQUV]T were made for various snow and ice surfaces in Hokkaido, Japan. The measurement

We present a new radiative transfer and retrieval pipeline, referred to as RISOTTO, designed for observations made in occultation geometry. RISOTTO can retrieve accurate vertical profiles of the constituents of a planetary atmosphere using a Bayesian approach while simultaneously correcting for instrumental artefacts and uncertainties. The algorithm makes use of a rapid Abel integration scheme involving

Line coupling and line mixing effects of CH3Cl lines in the ν1 band perturbed by N2 have been investigated. We have taken into account the non-diagonality of the exp(−S2) operator within specified line spaces as well as the k-degeneracy of the transitions (due to the double degeneracy of the j,k levels with k ≠ 0). These transitions should be considered as doublets coupled by the line mixing process

Two sets of NH3 absorption spectra covering the 0.793 μm region are recorded using two Bruker IFS 125 HR Fourier transform spectrometers. Three unapodized absorption spectra are recorded in Brussels over the range 11000−14500 cm−1 and the positions and intensities of 1114 ammonia lines observed in the 12491−12810 cm−1 region are measured using a multi-spectrum least squares fitting algorithm. 367 additional

A recent work has been devoted to the study of the Rayleigh limit of generalized Lorenz-Mie theory for on-axis beams in the case of non dark axisymmetric beams of the first kind. The present work complements this previous work by studying the case of non-dark axisymmetric beams of the second kind and of dark axisymmetric beams. This paper being presumably the last one of a series devoted to the Rayleigh

CH3I-oxygen line-broadening coefficients at 296 K are calculated for the RR, PR, RP, PP, RQ and PQ sub-branches of the ν6 band in a wide range of rotational quantum numbers (0≤J≤70, K≤20 by a semi-classical and a semi-empirical methods. The computed values compare very favourably with the available experimental data and therefore can be safely employed as estimates of broadening coefficients missing

Flaring plays a critical role in reducing the environmental impact of upstream oil and gas processing by converting methane and other gaseous hydrocarbons into CO2, which has a lower global warming potential. This process is highly efficient under ideal conditions but efficiency may be significantly lower under certain scenarios such as fuel stripping under crosswind and emission of volatile organic

A detailed study of the three interacting low-lying electronic states 2Δ, 2Σ+ and 2Π of NiH –the so called “supermultiplet” – is presented. A coupled-channels model reproduces the experimental term values of 58NiH, 60NiH and 62NiH with accuracy very close to the estimated uncertainty of 0.01 cm−1. The model is based on a set of Hund’s case (a) potential curves and R-dependent coupling functions. In

We report the discovery of seven even-parity energy levels of the Lanthanum atom. These levels are derived from experimental results which are quite difficult to interpret, since most of the investigated structures appear in complicated blend situations. 17 spectral lines can be classified as transitions in which these levels are involved. Further we could improve the J-values and hyperfine structure

The benefits of using a machine learning approach in a forward operator for visible satellite images are explored. In the conventional version of the forward operator, cloud-affected reflectances are determined by linear interpolation in a compressed, seven-dimensional look-up table (LUT) computed with standard radiative transfer (RT) methods. It is demonstrated that replacing the LUT by a feed-forward

Several past studies have described how absorption spectroscopy can be used to determine spatial temperature variations along the optical path by measuring the unique, nonlinear response to temperature of many molecular absorption transitions and performing an inversion. New laser absorption spectroscopy techniques are well-suited to this nonuniformity measurement, yet present analysis approaches use

Accurate knowledge of line parameters, and particularly line intensities is of primary importance for satellite, ground based and balloon measurements of the ozone concentration in the atmosphere. Self-consistency in absolute band intensities of ozone in various spectral intervals is necessary to avoid discrepancies in the atmospheric ozone retrieval from different windows. Difficulties in precise

We developed a principal-component based inversion approach – CIMAP, to retrieve aerosol properties from AERONET measurements of aerosol optical depths (AODs) and sky radiances. Capitalizing on the correlation in aerosol properties, CIMAP reduces the aerosol retrieval parameter space and saves retrieval time by more than 80% from adopting 7-8 principal components in the retrieval process, compared

We study the propagation of radiative heat (Marshak) waves, using modified P1-approximation equations. When the heat wave propagation is supersonic, i.e. propagates faster than the sound velocity, hydrodynamic motion is negligible, and the wave can be described by the radiative transfer Boltzmann equation, coupled with the material energy equation. However, the exact thermal radiative transfer problem

Considering the importance of the aerosol optical parameters detection for environmental monitoring, a method of converting single-wavelength Raman lidar backscattered echoes to aerosol mass concentrations is proposed to obtain a high-resolution vertical distribution of particulate matter (PM) mass concentrations. PMx (x = 1, 2.5, 10) mass concentrations and extinction coefficients at 355 nm and 532

We report the transition energies and probabilities of satellite lines due to 2p2(3P0,1,2)→1s2p(3P0,1,2) transitions of He-like C,Ne,Al and Ar ions embedded in strongly coupled plasma (SCP) environment. The SCP environment is represented by the ion-sphere (IS) model and the IS radius is varied in such a way that plasma electron densities (∼1020−1026 per cm3) cover a wide range of experimental interest

Using multi-beam optical tweezers is an effective and convenient way to create optical lattices and manipulate micro-particles. We study how the number of incident beams and polarization state of them and their angle of incidence influence the optical force resulting from optical lattices created on the plane of boundary to semi-infinite media on an arbitrary size dielectric spherical particle. Furthermore

The rotational structure of the A1Π(v = 2) level of 12C18O is re-examined using high-accuracy experimental data comprised of 541 molecular lines obtained by two complementary Fourier-transform techniques. The far ultraviolet absorption spectrum of the A1Π – X1Σ+(2, 0) band, in the range 66,500 - 67,650 cm–1, was recorded by the vacuum-ultraviolet FT spectrometer at the DESIRS beamline of the SOLEIL

In continuation of our previous publication on experimental laser spectroscopic investigations of the spectrum of the praseodymium atom in the visible region, the present paper reports the discovery of 65 new odd-parity fine structure levels of Pr I. Pr I atoms sputtered in a low-pressure hollow cathode discharge lamp were excited using tunable laser light. The excitation wavelengths were selected

We compare two methods of characterizing the radiative behavior of 22% porous sintered alumina disks containing μm-sized pores on the 1 µm to 7 µm wavelength range up to very high temperatures. The first consists of direct spectroscopic measurements of the normal-hemispherical reflectance and transmittance at room temperature, as well as the normal emittance up to 1300 ∘C. The second is a two-step

We measured terahertz (THz) pulses using a 18.6 m propagation distance multipass cell according to water vapor density (WVD) from 1.81 to 16.31 g/m3. The measured power attenuation was smaller than that obtained by the recommendation of the Radiocommunication Sector of the International Telecommunication Union (ITU-R) P. 676–12 (08/2019) database. To compensate for this difference, we proposed a modified

In a recent paper published in the journal Nature physics [1], a possibility to measure the fully differential cross section of the reaction of single Compton ionization of a helium atom without detecting the scattered photon has been demonstrated. A comparison of the experimental data with the theory based on the Kramers-Heisenberg-Waller model has shown a good applicability of this model to the case

Radiative sky cooling reduces the temperature of an object by exchanging heat with the cold universe through the sky. Such radiative cooling mechanism exists in nature but with lower cooling efficiency. For effective radiative cooling, the surface of an object should have high reflectivity in the solar spectrum and high emissivity in Earth's atmospheric transparent window (8-13 µm). In this work, we

We propose a physical optics approach to compute the volume radiative properties and surface reflectivity of porous ceramics composed of a weakly absorbing solid matrix containing low fractions of heterogeneities (pores or particles). Our approach accounts for dependent scattering between heterogeneities that are small and close to each other compared to the wavelength, and only requires the 3D microstructure

We use three independent spectroscopic techniques, operating in the millimeter-wavelength range, to study molecule-atom collisions, and validate our quantum-scattering calculations on two recent potential energy surfaces. We study the first pure rotational transition in a CO molecule perturbed by Ar. This molecular system is a good prototype of atmospherically relevant cases. It is, on the one hand

Optical identification, classification and quantification of different oil slicks play important roles in oil-slick monitoring and detection. Under the actions of wind, waves and other marine forces, oil slicks on the sea surface mix with seawater to form oil-seawater emulsions. Herein, we focus on the spectral radiative properties of seawater-in-oil emulsions in the visible-infrared region. The complex

Wavelength modulation-direct absorption spectroscopy (WM-DAS) has been used to measure the absorption line shapes of the H2O transition at 7299.431 cm−1 and the CO transition at 4297.705 cm−1 perturbed by Ar, N2 and He. The foreign-gas broadening, narrowing and pressure-shift parameters were determined from various lineshape models at pressures from 1 to 100 kPa. The measured N2-broadening coefficients

Multi-longitudinal-mode high-spectral-resolution lidar selects an optical interferometer with the periodic transmittance function as the spectral discriminator to separate aerosol Mie scattering signals and molecular Rayleigh scattering signals excited by the multi-longitudinal-mode pulsed lasers, such as Mach-Zehnder interferometer, Michelson interferometer, Fabry-Perot etalon and so on. In this paper

To model and design light propagation in disordered optical nanostructures and materials, any applicable simulation technique has to cope with enormous computational challenges in a bearable time frame. To circumvent these, the introduction of an artificial periodicity to the disordered particle structure allows to rely on computational techniques that exploit periodic boundary conditions. Choosing

The extinction behavior of various-shaped and core-shell-structured lanthanum hexaboride (LaB6) nanoparticles was theoretically studied based on the discrete dipole approximation method. It was found that different nanoparticle shapes yielded a great influence on extinction efficiency. In comparison to spherical and cubic particles, the near-infrared (NIR) extinction peak of rod-like nanoparticles

Precise spectroscopic measurements of isotope shift (IS), Δσ (160Dy - 164Dy) have been carried out in the 258 atomic emission lines of neutral dysprosium covering 555–833 nm wavelength region, of which IS data for 198 lines is being reported for the first time. The present measurements have contributed significantly to understanding the complex Dy I atomic structure, which enabled us to report the

The shape of the J = 0→1 rotational line of HC15N at 86 GHz has been recorded in collision with various polar and diatomic molecules and with all rare gases within the 135-300 kelvin temperature range. The coherent transient technique employed, optical precession in the time domain, has revealed as very propitious to analyze departures observed from the Voigt profile. First, a detailed analysis of

Despite decades of diligent work on their development, line-by-line (LBL) spectroscopic information systems, widely employed by scientists and engineers, may still contain a number of incorrect rovibronic lines. A novel heuristic protocol, relying on cycle bases of spectroscopic networks (SN) and a system of linear constraints, is proposed to unravel incorrect transitions present in the database. The

Atmospheric hydrofluorocarbon (HFC) abundances are increasing rapidly because of the Montreal Protocol phase-out of the production and consumption of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). HFC-32 (CH2F2, difluoromethane) mole fractions (volume mixing ratios, VMRs) have been retrieved from infrared absorption spectra recorded from orbit with the Atmospheric Chemistry Experiment

The analysis of the vacuum spark spectrum of erbium in the wavelength region 705 - 2460 Å has been extended. A total of 1022 spectral lines are newly identified as transitions between the low lying configurations 4f11, 4f105d, 4f106s and 4f106p of the Er3+ ion (Er IV), in addition to the confirmed previously identified 582 ones. The extended analysis has led to the determination of 168 new energy levels

As infrared telescopes are finding evidence of methane in hot exoplanet atmospheres, it is becoming increasingly important to have accurate high-temperature methane absorption models. To evaluate and update several spectroscopic databases (HITRAN2016, HITEMP, ExoMol), we collected laboratory spectra of the methane icosad (6770-7570 cm-1) using a 200 MHz (0.0067 cm-1) dual frequency comb spectrometer

A Bruker IFS 125HR Fourier-transform spectrometer has been used to measure pure carbon dioxide transmittance spectra in the spectral range 6000–7000 cm−1, including the bands 30011-00001, 30012-00001, 30013-00001, 30014-00001, and 00031-00001. A total of 10 measurements with absorption path lengths between 14.6 and 59.4 m and sample pressures from 3 to 80 mbar were performed at 295 K. A multispectrum

High resolution infrared spectra of PH3 were recorded with a Bruker IFS125 HR Fourier transform infrared spectrometer at an optical resolution of 0.0025 cm−1 and analyzed in the region of 600–1700 cm−1 where the ν2/ν4 bending dyad is located. The number of 2207 and 4564 transitions (in general, 3099 “allowed” and 3672 “forbidden”, which is about 2.5 times higher in comparison with the preceding studies)

One of the important signatures of non-thermal high-atomic-number multiply ionized plasmas is polarization of hard x-ray line emission. Atomic processes in laboratory and astrophysical plasmas with anisotropic electron distribution that can lead to such polarization include dielectronic recombination. All previous research on x-ray line polarization of dielectronic satellite lines was mostly focused

When a particle is charged, electrons can move freely along its surface and influence its optical properties in the same way as a thin, nonuniform metallic layer. These electrons contribute to scattering phenomena, including resonances. We model the light scattering from charged particles and demonstrate that these resonances result from excitation of an anti-symmetric surface plasmon at the layer

In this note it is suggested that the complex number rational approximations of Weideman and Humlíček may be replaced with the real number approximations of Abrarov / Quine and Kuntz respectively in the technique suggested by F. Schreier (JQSRT 112(6) (2011) 1010–1025) to provide an accurate Voigt function calculation algorithm with reduced calculation time targeting HITRAN database calculations. The

A limited number of studies have measured OH vibrational temperatures due in part to the difficulty of simultaneously observing multiple ro-vibrational emission bands. With questions still remaining about the quenching processes of the vibrationally excited OH molecule, observations of vibrational temperatures are critical to better characterize OH vibrational distributions. The Einstein A transition

The Lande gJ factors for high lying states of the argon atom by laser optogalvanic spectroscopy were measured, in most cases with an uncertainty of less than 0.005. The Zeeman structure of 12 argon lines with wavelengths in the range 598.7-612.8 nm was investigated. We determined Lande gJ factors for 9 odd parity levels and verified the data for several other levels.

Current methods for stochastic media transport are either computationally expensive or, by nature, approximate. Moreover, none of the well-developed, benchmarked approximate methods can compute the variance caused by the stochastic mixing, a quantity especially important to safety calculations. Therefore, we derive and apply a new conditional probability function (CPF) for use in the recently developed

Kirchhoff's law plays a vital role in radiation heat transfer, which has been recently generalized to hold for both reciprocal and nonreciprocal materials. However, the verification of the generalized Kirchhoff's law for nonreciprocal materials in experiment has not been reported. Previous proposed structures could only obtain strong nonreciprocal radiation at large angles, which were not favorable

The screening induced by a dense plasma environment is crucially important for determining radiative atomic data including bound–bound radiative decay rates and photoionization cross sections, which are vital for obtaining accurate opacity. Previous experimental investigations of ionization potential depression have shown that the widely used analytical models of screening struggle to capture the essential

A detailed spectroscopic study on ethyl methyl carbonate, a green solvent, has been carried out by recording vacuum ultraviolet and infrared spectra. The vacuum ultraviolet photoabsorption spectrum is recorded using synchrotron radiation from Photophysics beamline at the Indus-1 synchrotron radiation source at RRCAT, Indore, India in the wavelength region of 7–11.5 eV. Infrared spectra in gas phase

Passive Daytime Radiative Cooling (PDRC) process radiates excess heat by dumping heat into space through Transparent Atmospheric Windows (TAWs). Many structures are proposed for the PDRC but their main constraint is achieving near unity selective emission over 8–13 µm (first TAW, i.e., TAW 1) and 16–26 µm (second TAW, i.e., TAW 2) wavelength regions. In this paper, we have presented two Passive Daytime