Rayleigh light scattering from hydrogen‐bonded dimers of small astrophysical molecules

Abstract

High level ab initio calculations of the Rayleigh scattering activities of the hydrogen-bonded dimers of formic acid (HCOOH), nitrosyl hydride (HNO), and hydrogen cyanide (HCN) molecules have been performed. All these molecules have already been detected in interstellar space and are of great importance from the astrochemical point of view. The geometries of the homo-and hetero-dimers have been optimized using Hartree-Fock and second-order Møller-Plesset perturbation theory. Dipole moment, mean dipole polarizability, and polarizability anisotropy have been calculated utilizing Pople-type 6-311þþG(d,p) and Dunning's aug-cc-pVDZ basis sets for all the complexes. The polarizabilities are then used to calculate and analyze the Rayleigh scattering parameters. The results for the dimers, HCNÁÁÁHCN, HCOOHÁÁÁHCOOH, HNOÁÁÁHNO, HCNÁÁÁHCOOH, HCNÁÁÁHNO, and HNOÁÁÁHCOOH are compared with those of the isolated molecules, HCN, HCOOH, and HNO to see the effect of hydrogen bond formation on the molecular interaction with radiation.

Antifungal Activity and Computational Study of Constituents from Piper divaricatum Essential Oil against Fusarium Infection in Black Pepper

“…The nature of hydrogen bond interactions is still today the subject of many discussions and its importance in enzymatic environment has been shown in some drug design studies [31,32]. In this study, the hydrogen bond interactions were the main interactions found in protein-ligand complex as previously discussed.…”

Structure and NLO properties of halogen (F, Cl) substituted formic acid dimers

“…Light scattering cross-section and depolarization are related to the anisotropy of the electronic polarization of a molecular system. In the elastic Rayleigh scattering, the degree of depolarization (r) of the incident light scattered at right angles to the direction of incidence for natural, plane-polarized, circularly polarized light and Rayleigh activity (R) can be expressed in terms of the mean polarizability and polarizability anisotropy [41,[62][63][64][65] as follows: where R n is the Rayleigh activity for the natural light, while R p\ and R pll are the polarized light with polarization being perpendicular and parallel to the scattering plane, respectively. The elastic Rayleigh scattering cross section and depolarization, related to the anisotropy of the dipole polarization (Da) were calculated using DFT method.…”

“…FA dimer forms a variety of hydrogen-bonded structures, which is of primary importance for many processes, including the science of life [40]. Earlier studies on the NLO property of formic acid dimers [41], have shown that the value of dipole polarizability are twice when compared with their monomer form. To, further increase the NLO property of formic acid dimers, halogen substitution to the carbon atom might be a solution, as we know halogen substituent draws the electrons in the CAX bond toward itself, giving the carbon a partial positive charge (d+) and the halogen a partial negative charge (dÀ).…”

Effect of alkyl chain on the NLO property of nonylphenol isomers: a DFT study

“…The value of the depolarization ratios (r n , r p , and r c ) of few NP isomers follows a linear trend with their corresponding Da values (Table 2). It is to be noted that the depolarization ratio value of circularly polarized light is higher in magnitude followed by natural and plane polarized light [63]. Considering the Rayleigh intensity values, on the whole, isomer NP3 with highest polarizability value possesses the maximum R n and R p?…”