English

Ab initio thermochemistry beyond chemical accuracy for first-and second-row compounds

Chemical Physics 2007-05-23 v1

Abstract

By judicious use of extrapolations to the 1-particle basis set limit and nn-particle calibration techniques, total atomization energies of molecules with up to four heavy atoms can be obtained with calibration accuracy (1 kJ/mol or better, on average) without any empirical correction. For the SCF energy a 3-point geometric extrapolation is the method of choice. For the MP2 correlation energy, a 2-point A+B/(l+1/2)3A+B/(l+1/2)^3 extrapolation is recommended, while for CCSD and CCSD(T) correlation energies we prefer the 3-point A+B/(l+1/2)CA+B/(l+1/2)^C formula. Addition of high-exponent `inner polarization functions' to second-row atoms is essential for reliable results. For the highest accuracy, accounts are required of inner-shell correlation, atomic spin-orbit splitting, anharmonicity in the zero-point energy, and scalar relativistic effects.

Keywords

Cite

@article{arxiv.physics/9808013,
  title  = {Ab initio thermochemistry beyond chemical accuracy for first-and second-row compounds},
  author = {Jan M. L. Martin},
  journal= {arXiv preprint arXiv:physics/9808013},
  year   = {2007}
}

Comments

43 pages, in upcoming NATO ASI volume "Energetics of stable molecules and reactive intermediates" (ed. M. E. Minas da Piedade)

R2 v1 2026-07-22T19:18:06.954Z