Skip to main content

A proposed modification of CBS-4M model chemistry for application to molecules of increasing molecular size

Abstract.

 In order to calculate more accurately the enthalpies of formation, ΔH f°(298 K), for large molecules using the CBS-4M method, a new formulation of the empirical higher-level correction to the energy is proposed: ΔE=a|S|2 i i I i i +b(n α+n β)+cΔ<S 2>+Σn i d i . The new methodology (CBS-4MB) applied to a set of 114 molecules of different size significantly decreases the mean absolute deviation from 3.78 to 2.06 kcal/mol.

This is a preview of subscription content, access via your institution.

Author information

Affiliations

Authors

Additional information

Received: 7 February 2001 / Accepted: 5 April 2001 / Published online: 13 June 2001

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Benassi, R. A proposed modification of CBS-4M model chemistry for application to molecules of increasing molecular size. Theor Chem Acc 106, 259–263 (2001). https://doi.org/10.1007/s002140100274

Download citation

  • Key words: Model chemistry – CBS-4M theory – Thermochemistry – Sulfur compounds – Ab initio molecular orbital methods