N2- and O2-broadening coefficients were measured at room temperature for 2914 ro-vibrational lines of methyl chloride in the region from 920 to 1140 cm−1 corresponding to the ν6 band, using a high-resolution Fourier transform spectrometer and a mono-spectrum non-linear least squares fitting of Voigt profiles. The spectra were recorded at the AILES beamline of the SOLEIL Synchrotron facility at various

The infrared spectrum of germane, purified and enriched up to 88.1 % of 76GeH4, was measured at the temperature of (22.6±0.1)∘C with a Bruker Fourier transform infrared spectrometer IFS125HR and analyzed in the region of 2350 – 2730 cm−1 where the bending tetrad of the ro–vibrational octad of germane is located. The 2955 transitions belonging to the thirteen sub–bands of the Tetrad were assigned and

We report on radiative lifetime and collisional cross section measurements of the Na2 61Σg+(v=6, J=31) and 61Σg+(v=8, J=31) molecular levels by time-resolved laser spectroscopy. The excitation to the 61Σg+(3s+5s) electronic state was achieved using two synchronized pulsed lasers, directed to the sodium heatpipe oven and molecular fluorescence decay time as a function of buffer gas was recorded via

For the 12C2H2D2-cis molecule a line strength analysis of 1473/400 transitions of the ν12/ν3 bands was performed by the fit of their line shapes with the Hartmann–Tran profile. Ten effective dipole moment parameters (six parameters for the ν12 band and four parameters for the ν3 band) were obtained from the weighted fit which reproduce the initial experimental 1473 transition strengths of the ν12 band

UV radiation can inactivate viruses such as SARS-CoV-2. However, designing effective UV germicidal irradiation (UVGI) systems can be difficult because the effects of dried respiratory droplets and other fomites on UV light intensities are poorly understood. Numerical modeling of UV intensities inside virus-containing particles on surfaces can increase understanding of these possible reductions in UV

A MATLAB package describing discrete dipole approximation (MPDDA) is introduced to calculate the optical properties of arbitrary shaped plasmonic nanoparticles (NPs). The polarizability function, induced dipoles, and dipole interaction matrix are discussed. To calculate the dipole moments, Fast Fourier Transform (FFT) and Biconjugate Gradient (BCG) were used to reduce the computational time and memory

We combine the transfer matrix based algebraic approach with the Green’s function method to theoretically study polarization resolved far-field angular distributions of photoluminescence from quantum nanorods (NRs) embedded in an optically anisotropic film. The emission and excitation properties of NRs are described by the emission and excitation anisotropy tensors. These tensors and the solution of

In this work, we propose and demonstrate that transverse Kerker scattering (TKS), previously achieved relying on simultaneous excitation of electric dipole (ED), magnetic dipole (MD), electric and magnetic quadrupoles, can also be simply realized via only two nondegenerate EDs in two-dimensional cylindrical structures. The principle indicates that, the TKS can be achieved as if two EDs oscillate antiphase

The contribution of soot aerosols to radiative forcing and climate change depends on their optical properties. Since these aerosols are agglomerates composed of quasi-spherical primary particles (usually small with respect to the radiation wavelength), their properties can be calculated following the Rayleigh-Debye-Gans approximation, which considers primary particles as independent absorbers and scatterers

This paper presents an extension to our knowledge of ∆v = 1 and ∆v = 2 bands of carbon monoxide in the ground state, measured by Fourier transform infrared spectroscopy of glow discharge of formamide-nitrogen mixture. Lines in declared bands are measured up to v = 30 for ∆v = 1 and up to v = 24 for ∆v = 2 band, by use of both InSb and MCT detectors, which have not been measured in the laboratory before

Using the multiconfiguration Dirac-Hartree-Fock (MCDHF) and the relativistic configuration interaction (RCI) methods, a consistent set of transition energies and radiative transition data for the lowest 150 states of the 3s23p3, 3s3p4, 3s23p23d, 3s3p33d, 3p5, and 3s23p3d2 configurations in P-like Ge XVIII is provided. To assess the accuracy of the MCDHF transition energies, we have also performed calculations

This paper quantifies experimentally the effect of pendant droplets condensed on the back of semi-transparent glass panes on their normal-hemispherical transmittance and reflectance in the visible and near-infrared. To enable sample characterization and ensure repeatability, acrylic droplets were deposited on the back side of 3 mm-thick soda-lime silicate glass slabs with or without hydrophobic surface

The 19 Λ-S states and the low-lying Ω states of NaS molecule are computed by using the multireference configuration method (MRCI) including spin-orbit coupling (SOC), core-valence correlation (CV), scalar relativistic effects and Davidson (+Q) correction. The potential energy curves (PECs), spectroscopic constants and dipole moments are obtained. The predissociation mechanism of A2Σ+ is investigated

The Rayleigh limit of the generalized Lorenz–Mie theory (GLMT) and its relationship with the dipole theory of forces is investigated for transverse radiation pressure cross-sections and optical forces exerted over very small particles. If, at one hand, the GLMT provides interesting insights in terms of a multipole expansion and becomes restricted to contributions from (n=1)-partial waves, on the other

Convolution neural networks were applied to classify speckle images generated from nanoparticle suspensions and thus to recognise suspensions. The speckle images in the form of movies were obtained from suspensions placed in a thin cuvette. The classifier was trained, validated and tested on both single component monodispersive suspensions, as well as on two-component suspensions. It was able to properly

The key to the micro/nanoscale thermal management of precision instruments is flexibly controlling the heat flux in the near-field following the actual demand. In this paper, a near-field radiative thermal switch (NFRTS) made of the n-type doped silicon (D-Si) and graphene-covered silicon dioxide (SiO2) plates is proposed to achieve the active near-field radiative heat transfer modulation. The radiative

Various spectroscopic data for absorption lines due to the magnetic dipole transitions of the a1Δg−X3Σg−(0−0) band of O2 centered at 1.27 µm are tested by comparison with high-resolution ground-based atmospheric measurements recorded by Fourier Transform Spectrometers at Park Falls and Caltech (USA). This band is of importance for atmospheric remote sensing since it will be used (together with the

CALIPSO (cloud-aerosol lidar and infrared pathfinder satellite observation) provides unique opportunities for profiling global cloud and aerosol. It is crucial to accurately detect the boundaries of cloud and aerosol layers from CALIPSO observation because the detecting error will be passed to further retrieval. Considered superior to other layer detection methods, the threshold method is the core

A ground-based high-spectral-resolution lidar (HSRL), operated at 532 nm wavelength, has been developed at Zhejiang University (ZJU) for aerosols and clouds studies. This lidar provides vertical profiles of aerosol scattering ratio together with lidar ratio and particle depolarization ratio at 532 nm. These single wavelength HSRL observations can be used to automatically identify the features attributed

We analyze the optical radiation forces, produced by a focused rotational elliptical Laguerre-Gaussian correlated Schell-model (ELGSM) beam, on the dielectric particles of different refractive indices in the Rayleigh scattering regime. It is found that through a judicious modulation of the initial spatial coherence width and the beam order of the correlation function of the rotational ELGSM beam, the

Scanning-wavelength laser absorption measurements were carried out to determine the line strengths and broadening coefficients due to collisions of N2, O2, Ar, He, and NH3 for 12 ammonia transitions in the Q-branch of the v2 fundamental band near 10.4 µm. The measurements were conducted at 296 K using a high-resolution quantum cascade laser and span the frequency range of 957.5–963.0 cm−1. The absorption

Airborne measurements of the linear polarization state of light were carried out over coastal and open ocean conditions to study aerosol and water column properties and investigate the possibility of using a multi-spectral, hyper-angular imaging polarimeter for retrieving aerosol and hydrosol optical properties. The instrument, the Versatile Imager for the Coastal Ocean (VICO), is used to support the

A new instrument, the Polarized Scanning Nephelometer (PSN), has been developed for measuring the complete scattering matrix of aerosol particles as a function of the scattering angle. The instrument measures directly the ensemble-averaged scattering matrix elements of the aerosol particles and can deduce all scattering matrix elements for scattering angles in the range 3.5° to 170° at two different

While the CERES input aerosol optical depth and precipitable water data are continuously available, the same parameters derived from BSRN site measurements are available only intermittently. Cloudiness disrupts the aerosol optical depth (AOD) retrieval and precipitable water (w) observation sampling. Irregularly sampled records, such as these, can cause systematic biases if the averages of the continuous

We analyze the possibilities of orbital photopolarimetric measurements to study properties of aerosols in the Earth's atmosphere. As an example, we consider the case when such measurements are performed within a narrow spectral channel centered at 1.378 µm that allows to retrieve microphysical characteristics of stratospheric aerosols separately from those of tropospheric aerosols. We consider the

In continuation to a series of works on the elaboration of Finite Series (FS) methods for helical beams under the Generalized Lorenz–Mie Theory’s formalism, this paper consists of a thorough study of the mathematical and computational nuances which arise from implementing the recently deduced FS method for Lens–Focused Laguerre–Gaussian beams. This family of beams, as in most brought under the FS procedure

The measurement of particle size distribution (PSD) in colloids and nanofluids presents many challenges, especially when it requires to be conducted in-situ and real-time. Our work aims to assess the capabilities of Light Extinction Spectroscopy (LES) technique to determine concentration and volumetric PSD (vPSD) of colloids and nanofluids. Numerical simulations are performed to verify robustness of

Plane light waves can carry angular momentum which is usually longitudinal (i.e. oriented along the axis of propagation). However, in confined (focused) light waves it can be oriented transversely (or perpendicular to the direction of propagation). Such electromagnetic fields therefore are called ‘photonic wheels’. We create photonic wheels with an aplanatic system and expand them into vector spherical

Nanowire arrays are promising man-made materials for tuning the spectrum and the magnitude of near-field thermal radiation. Near-field radiative properties of nanowire arrays are often studied using the effective medium theory (EMT). In this paper, we inspect the validity of the Maxwell-Garnett (MG) and Bruggeman (BR) EMTs for predicting near-field thermal emission by quartz and indium tin oxide (ITO)

This paper investigates optical forces on absorptive Rayleigh particles produced by a nondiffracting microstructured vectorial beam (micrometer Frozen Wave) designed from a continuous superposition of first-order Bessel beams, very adaptive to highly nonparaxial conditions. Carrying a non null topological charge and possessing a vector nature, these beams have both orbit and spin angular momentum.

Ni atoms, produced in the Earth's upper atmosphere by meteoric ablation, are challenging to measure by lidar because the Ni atom density is low, the resonance scattering cross section is relatively small, and the transitions occur in the near-UV around 340 nm where absorption by the stratospheric ozone layer starts to become significant. A new Ni lidar has been designed and deployed at Yanqing station

Elastic backscatter lidar is an established method useful to characterize the particles forming an atmospheric aerosol. Fundamental to lidar measurements are the extinction and backscattering properties of the aerosol particles in the lidar beam. This review aims to give the reader an understanding for how lidar measurements are made, modeled, and applied. Specific emphasis is placed on extinction

Polarization in the Lyman-α line caused by anisotropic electron collisions has been investigated in the Large Helical Device (LHD). High-sensitivity polarization-resolved measurements of the Lyman-α line from edge LHD plasma have been carried out. To obtain spectra of linearly polarized light at all angles a high-reflectivity mirror, a polarization analyzer, and a half-waveplate have been additionally

The study of optical forces exerted by off-axis Bessel beams on Rayleigh particles in the framework of generalized Lorenz-Mie theory demonstrated the existence of extra-forces named axicon forces, complementing the classical scattering and gradient forces already discussed extensively in the literature. The present paper revisits the same issue but in the more restricted case of on-axis beams. Results

This paper presents a relatively simple method for temperature measurement of hot carbon dioxide gas using an emission spectroscopy setup. The ν3 band emission at 4.3 µm is detected using an optical band-pass filter and a mercury cadmium telluride detector. A conversion methodology is introduced that calculates the detector voltage from the spectral radiance considering the spectral sensitivities of

Daytime radiative cooling has drawn much attention recently because a target surface can be passively maintained at sub-ambient temperature. In order to implement a daytime radiative cooling device (simply ‘radiative cooler’), strong thermal emission should be focused in the mid-infrared regime (8–13 µm), called ‘atmospheric transparent window’. At the same time, absorption of the solar irradiation

An exact semi-analytical solution to a scattering problem of evanescent wave incident on a particle is obtained. The evanescent wave is generated by total reflection as an electromagnetic plane wave propagates from an optically denser medium to an optically thinner one. The scattered fields by and internal fields within the particle are expanded in terms of spherical vector wave functions, and an integral

We demonstrate a new method for populating line-by-line spectroscopic databases with beyond-Voigt line-shape parameters, which is based on ab initio quantum scattering calculations. We report a comprehensive dataset for the benchmark system of He-perturbed H2 (we cover all the rovibrational bands that are present in the HITRAN spectroscopic database). We generate the entire dataset of the line-shape

Backward fluorescence of thick atomic vapors exhibits a dip in the spectra at line center and sub-Doppler structures. We present backward fluorescence spectra of cesium vapor when excited around D2 line for densities for which atoms undergo a few collisions before emitting a photon. Changes on dip symmetry relative to line center and of sub-Doppler structures are observed. We perform Monte-Carlo simulations

Within the framework of Breit Pauli R-matrix approach, a close-coupling calculation has been carried out for the process of photoionization of ground and excited states of Ne-like Mo XXXIII ion. The calculation includes 60 fine-structure levels and 15 parities for the target states. Level specific photoionization cross sections are computed for all levels at a fine energy mesh of 10−5 scaled Ryd, with

The immersed boundary method (IBM) was developed for the first time in the present study to simulate the radiative heat transfer problems in complex geometries. The pseudo time stepping technique was applied to solve the radiative transfer equation (RTE) using the finite volume method (FVM). Also, the direct forcing-sharp interface was used in IBM. This method was validated with some benchmark problems

In this work, all-electron ab initio calculation on the SbI molecule has been carried out with the multi-reference configuration interaction plus the Davidson correction (MRCI+Q) method. In the calculation, total 34 Λ-S states have been obtained for the first time. From calculated PECs, the derived spectroscopic constants well agree with available experimental values. It should be mentioned that A3Π

Vibrational energy levels of H2CO are reported using variational nuclear motion calculations from new ab initio and empirically optimized full 6-dimensional ab initio potential energy surfaces in the ground electronic state of the formaldehyde molecule. Ab initio calculations were carried out using extended electronic structure coupled-cluster calculations accounting for dynamic electron correlations

The water vapor line at 183 GHz was studied over the temperature range of 219-358 K using a spectrometer with radioacoustic detection of absorption, providing a signal-to-noise ratio of up to 8000. The study includes the first measurement of speed-dependent collisional broadening and shifting of this line for both self- and air-broadening, and their temperature dependences. The sign of self-shifting

Laser spectroscopy and optogalvanic detection was applied to investigate up to now unclassified or even unknown spectral lines of atomic lanthanum (La I). The exciting laser light had wavelengths between 4300 and 6800 Å. We report the discovery of seven new energy levels. One additional level turned out to be already known, but with wrong angular momentum. Altogether 53 spectral lines could be classified

Carbon tetrafluoride (CF4), also known as tetrafluoromethane and sometimes CFC-14, has a natural lithospheric source, however the enhanced modern-day concentrations relative to this natural source have arisen from leaks into the atmosphere by industry, most significantly related to the production of aluminium and semiconductors. A potent greenhouse gas, with one of the longest atmospheric lifetimes

Soot, a product of insufficient combustion, is usually in the form of aggregate. The multi-scattering of soot fractal aggregates has been proved to play an important role in studying the soot radiative properties, which is rarely considered in predicting the radiative heat transfer in combustion flame. In the present study, based on the Rayleigh-Debey-Gans-Fractal-Aggregate (RDG-FA) theory, a model

In this paper, a controlled-laboratory experiment is carried out to evaluate the lidar depolarization ratio of freshly emitted soot aggregates in the exact backward scattering direction at 180.0°. The experiment is performed at two wavelengths simultaneously, namely 355 and 532 nm, often used in polarimetric lidar remote sensing. The soot aggregates are generated from a kerosene JET A-1 pool fire in

We propose a wavelength-selective emitter using nanoslit graphene metasurface. The nanoslit graphene metasurface consists of a graphene sheet, metallic slit, and dielectric layer for tailoring radiative properties. The utilization of rigorous electromagnetic simulation clarifies the mechanisms of thermal radiation. The proposed emitter shows high emissivity and a broad peak wavelength shift because