Rovibrational energy and spectroscopic constant calculations of CH 4 ⋯ CH 4, CH 4 ⋯ H 2 O, CH 4 ⋯ CHF 3, and H 2 O ⋯ CHF 3 dimers

Abstract

In this work, we performed a thorough investigation of potential energy curves, rovibrational spectra, and spectroscopic constants for dimers whose interactions are mediated by hydrogen bonds and other hydrogen interactions. Particularly, we deal with CH4⋯CH4, CH4⋯H2O, CH4⋯CHF3, and H2O⋯CHF 3 dimers by employing accurate electronic energy calculations with two different basis sets at the MP2 level of theory. Following this, the discrete variable representation method was applied to solve the nuclear Schrödinger equation, thus obtaining spectroscopic constants and rovibrational spectra. The harmonic constant, ω e , presents a direct relation to the strength of dimer interactions. As a general rule, it was found that a decrease of interatomic distances is followed by the increase of D e for all dimers. This behavior suggests that the interaction of CH4⋯CH4 is the weakest among all dimers, followed by CH4⋯CHF3, CH4⋯H2O and the strongest interaction given by the H2O⋯CHF 3 dimer.

The van der Waals interactions in systems involving superheavy elements: the case of oganesson (Z = 118)

“…The second analytical form was the extended-Rydberg 28 function, which has been used successfully to describe various molecular systems [29][30][31] and it is described according to the equation:…”

“…The second analytical form was the extended-Rydberg 28 function, which has been used successfully to describe various molecular systems 29–31 and it is described according to the equation:where c i are adjustable coefficients. Once the analytical forms that fit the electronic energies are known, one can solve the nuclear Schrödinger equation (within the Born–Oppenheimer approximation) and determine the vibrational energies of the molecules under study.…”

Ab Initio Approach to the Structure, Vibrational Properties, and Electron Binding Energies of H2S∙∙∙SO2

“…Applying methods developed in theoretical chemistry enables a comprehensive analysis of the structure and energetics of molecular systems, relying on a fundamental understanding of intermolecular interactions [ 18 , 19 , 20 , 21 , 22 ]. In the case of H 2 S∙∙∙SO 2 , there is evidence suggesting that the interactions occurring in this system are primarily associated with S∙∙∙S chalcogen–chalcogen interactions [ 23 , 24 , 25 , 26 ].…”