Calculation of the average properties of atoms in molecules. II

Abstract

This article describes an algorithm for the calculation of the average properties of an atom in a molecule. The atom is defined within the topological theory of molecular structure, a theory which defines atoms, bonds, structure, and structural stability in terms of the topological properties of a system's charge distribution. The average properties of the atom so defined are uniquely determined by quantum mechanics. Results for a number of hydrocarbon molecules, obtained by the program PROAIM (properties of atoms in molecules) which implements this algorithm, are given. In general, this program enables one to calculate the average energy of an atom in a molecule to an accuracy of ±1 kcal/mol.

Theoretical Study on the Urea−Hydrogen Peroxide 1:1 Complexes

“…The BSSE was estimated using the full counterpoise method, 44 as previously described. [20][21][22] The Bader analyses were performed with the AIMPAC series of program 45 using the MP2 wave function as input, as described in Atoms in Molecules Theory. 46,47 The topology of the electronic charge density (F(r)), as pointed out by Bader, 46 is an accurate mapping of a chemical concept of atom, bond and structure.…”

Experimental and computational studies of the macrocyclic effect of an auxiliary ligand on electron and proton transfers within ternary copper(II)-Histidine complexes

“…The topological properties of the electron density distribution of each molecule were determined based on the gradient vector field of the electron density (r) and on the Laplacian of the electron density ٌ 2 (r), where r is the positional vector of an electron in threedimensional space. The molecular graphs-including bond critical points (BCPs), ring critical points (RCPs), and cage critical points (CCPs)-and the bond paths were plotted using the AIM2000 program [34,35]; atomic integration [36] for each atom in a molecule, based on B3LYP/6-31ϩG(d) wave functions, was performed using the AIMALL program [37].…”

High resolution NMR of free radicals: 13C magic angle spinning of two solid organic free radicals derived from 4,5-dihydro-1H-imidazol-3-oxide-1-oxyl and theoretical calculation of their NMR properties

“…The electron density of the molecules has been analyzed within the atoms in molecules (AIM) methodology 43 with the AIMPAC and MORPHY98 programs. [44][45][46] The electron density molecular graphs have been represented with the MORPHY3 program. 47 In the NMR spectroscopy of paramagnetic systems several nonvanishing interactions between the nuclear and electron magnetic moments should be considered.…”