Prelude to molecular dynamics: Topography‐driven gaussian charge models

Abstract

A new strategy to develop Gaussian charge models (GCMs) for molecules like ammonia, water, ethene, hydrogen sulfide, formaldehyde and benzene is presented. These molecular models comprising of positive point charges and negative Gaussian charge distributions (GCDs), which represent nuclei and continuous electron charge distribution, are found to correctly represent the ab initio Molecular Electrostatic Potential (MESP) and reproduce its essential topographical features of corresponding molecules. The models use optimized parameters: positive charges at nuclei, negative charges on GCDs, Gaussian exponent and centers. The Potential Energy Surface (PES) of water dimer has been explored using water GCMs. A good agreement has been found between PES obtained using GCMs and wave function. The Gaussian models correctly predict structure of benzene‐water complex. It is thus recommended to use GCMs for molecular dynamic simulations.

Mechanistic study of the formation of arbutin polymorphs and solvates

“…For the molecular electrostatic potential (MEP) surface analysis, the molecular structures of arbutin and the solvents were first optimized by the DFT method in Gaussian software, 30 and the wave functions were obtained by the 6-311G++ (d, p) with the basis set of B3LYP. 31 Based on the wave functions, Multiwfn 3.7 was carried out for the MEPs analysis.…”

Polymorphs and Solvates of Molnupiravir: Crystal Structures and Solid Forms Transformation Analysis

“…Molecular Electrostatic Potential (MEP) Surface Analysis. The molecular structures of MPV and solvent molecules were optimized using Gaussian 09 software, 34 and the wave functions were obtained by B3LYP with the basis set of 6-311G++ (d,p). The molecular electrostatic potential (MEP) isosurface's local minimum and maximum potential sites were generated using Multiwfn 3.8 software 35 and the VMD 1.9.3 program.…”

Prelude to Molecular Dynamics‐II: Investigation of Potential Energy Surfaces Using Gaussian Charge Models

“…In both: C 6 H 6 …H 2 O and benzene-ammonia (C 6 H 6 …NH 3 ) complexes, one of the hydrogen atoms belonging to H 2 O and NH 3 molecules is found to interact with the π cloud of aromatic substrate ( The underestimated IE s , [18] reported for several stationary points along PES of C 6 H 6 …H 2 O complex at MP2/6-31G(d,p) level of theory (Table 4, column 2) have been rectified (Table 4, column 4) by using vdW/spherical enclosures for respective GCMs. These stationary points were also optimized at MP2/ 6-31 + G(d,p) level of theory and corresponding geometries are displayed in column 5 of Table 4.…”

“…[17] The earlier study from our laboratory dealt with development of topography-based GCMs and demonstrated their reliability to be employed for molecular dynamics simulations as they were capable of predicting correct geometries of water dimer (H 2 O) 2 and benzene-water complex (C 6 H 6 …H 2 O). [18] In continuation with the same, the present study aims in rectifying the underestimated IE values reported for mentioned molecular systems and investigating potential energy surfaces (PESs) of several other interacting molecules using GCMs.…”