Self-consistent perturbation theory

Abstract

The density matrix form of Hartree-Foek perturbation theory is developed for the case in which the basis functions themselves are perturbation-dependent. Energy expressions are derived, through second order, for both single and double perturbations.The theory is applied in the calculation of electric dipole polarizabilities and hyperpolarizabilities for atoms (He, Be) and molecules (H2, LiH), with excellent results. The high computational efficiency of the method is discussed and possibilities of further development are outlined.

Understanding Sterol–Membrane Interactions Part I: Hartree–Fock versus DFT Calculations of 13C and 1H NMR Isotropic Chemical Shifts of Sterols in Solution and Analysis of Hydrogen‐Bonding Effects

“…[35,36] In all cases, among the various theories available to calculate chemical shielding tensors, the Gauge Including Atomic Orbital (GIAO) method was adopted for the numerous advantages it offers. [50][51][52][53][54] For geometry optimization, two strategies were tested: a computationally inexpensive one that combines the HF method with a minimal STO-3G basis set [44] and a more costly one that involves the B3LYP method and the 6-31G(d,p) basis set. If one then combines the structure and NMR problems, one obtains four computational schemes.…”

Accurate predictions of the EPR parameters in planar cobalt(II) complexes by hybrid density functional theory

“…To avoid gauge dependence of the g-values upon the origin chosen for the magnetic field if one uses a finite basis set, the gauge including atomic orbitals (GIAO) [42,43] method was used. The experimental geometries based on X-ray crystallographic data determined by Cariati and coworkers [44] were adopted.…”

Computational Study on Spirocyclic Compounds as Energetic Materials (I)

“…[9][10][11][12][13] In order to obtain accurate enthalpies and free energies, we applied the complete basis set (CBS) method of Petterson and coworkers. With a HF/3-21G(d) structure optimization, CBS-4 begins by computing the zero pont energy, it then uses a large basis set SCF calculation as a base energy, and a MP2/6-31+G calculation with a CBS extrapolation to correct the energy through second order.…”