Derivative studies in hartree-fock and møller-plesset theories

Abstract

The complete spin-orbital formulation of the analytical first and second derivatives of the Hartree-Fock (HF) energy as well as the analytical first derivative of the correlated second-order Mfller-Plesset perturbation energy (MP2) is presented. Some features of an efficient computational method to calculate these derivatives are described. The methods are applied to calculate the harmonic vibrational frequencies of ethylene, and the results are compared with experiment.

Identification of Diethyl 2,5-Dioxahexane Dicarboxylate and Polyethylene Carbonate as Decomposition Products of Ethylene Carbonate Based Electrolytes by Fourier Transform Infrared Spectroscopy

“…The systematic error in the calculated vibrational frequencies at the HF level was corrected by using an empirical scaling factor of 0.8929. 25 6 The -C(O)-carbon at 155.23 ppm shows a relatively lower abundance compared to the other carbons because it is an sp 2 -hybridized carbon peak. All chemical shifts of 1 H and 13 C nuclei are given in Table S1 (Supporting Information).…”

New donor–acceptor chromophores by formal [2+2] cycloaddition of donor-substituted alkynes to dicyanovinyl derivatives

“…[11] Stationary points were characterized by harmonic vibrational frequency analysis. [12] Molecular energies were calculated as the sum of the electronic energy and Gibbs free energy correction obtained cases compared to 2m rendering it rate-determining overall. A secondary influence beyond this, presumably steric, effect of the phenyl ring is felt from the electronic nature of the attached substituent at its para-position; the nitro-substituted derivative (2b) reacts through the lowest barrier, followed by the phenyl group (2h) and finally the N,Ndimethylamino-substituted reactant (2l).…”

Embedding Fragment ab Initio Model Potentials in CASSCF/CASPT2 Calculations of Doped Solids: Implementation and Applications

“…Because the fragment orbitals are also eigenfunctions of F clus (see equation 5), these terms should be added to similar terms occurring when determining the derivative of E clus in the HartreeFock case. 23 This means they are also included in the term…”