Abstract

This work characterizes eight stationary points of the P2 dimer and six stationary points of the PCCP dimer, including a newly identified minimum on both potential energy surfaces. Full geometry optimizations and corresponding harmonic vibrational frequencies were computed with the second-order Møller-Plesset (MP2) electronic structure method and six different basis sets: aug-cc-pVXZ, aug-cc-pV(X+d)Z, and aug-cc-pCVXZ where X = T, Q. A new L-shaped structure with C2 symmetry is the only minimum for the P2 dimer at the MP2 level of theory with these basis sets. The previously reported parallel-slipped structure with C2h symmetry and a newly identified cross configuration with D2 symmetry are the only minima for the PCCP dimer. Single point energies were also computed using the canonical MP2 and CCSD(T) methods as well as the explicitly correlated MP2-F12 and CCSD(T)-F12 methods and the aug-cc-pVXZ (X = D, T, Q, 5) basis sets. The energetics obtained with the explicitly correlated methods were very similar to the canonical results for the larger basis sets. Extrapolations were performed to estimate the complete basis set (CBS) limit MP2 and CCSD(T) binding energies. MP2 and MP2-F12 significantly overbind the P2 and PCCP dimers relative to the CCSD(T) and CCSD(T)-F12 binding energies by as much as 1.5 kcal mol-1 for the former and 5.0 kcal mol-1 for the latter at the CBS limit. The dominant attractive component of the interaction energy for each dimer configuration was dispersion according to several symmetry-adapted perturbation theory analyses. © 2014 Wiley Periodicals, Inc. Eight stationary points of the P2 dimer and six stationary points of the PCCP dimer are characterized with the second-order Møller-Plesset (MP2) electronic structure method. The canonical and explicitly correlated MP2 and CCSD(T) complete basis set limit binding energies are reported. Copyright © 2014 Wiley Periodicals, Inc.

Department(s)

Chemistry

Publication Status

Full Access

Comments

National Science Foundation, Grant 0903787

Keywords and Phrases

benchmark interaction energy; CCSD(T) complete basis set limit; dispersion interactions; noncovalent interactions; symmetry-adapted perturbation theory

International Standard Serial Number (ISSN)

1096-987X; 0192-8651

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Wiley, All rights reserved.

Publication Date

05 Mar 2014

Included in

Chemistry Commons

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