Accurate Excited-State Geometries: A CASPT2 and Coupled-Cluster Reference Database for Small Molecules.

ABSTRACT: We present an investigation of the excited-state structural parameters determined for a large set of small compounds with the dual goals of defining reference values for further works and assessing the quality of the geometries obtained with relatively cheap computational approaches. In the first stage, we compare the excited-state geometries obtained with ADC(2), CC2, CCSD, CCSDR(3), CC3, and CASPT2 and large atomic basis sets. It is found that CASPT2 and CC3 results are generally in very good agreement with one another (typical differences of ca. 3 × 10^-3 Å) when all electrons are correlated and when the aug-cc-pVTZ atomic basis set is employed with both methods. In a second stage, a statistical analysis reveals that, on the one hand, the excited-state (ES) bond lengths are mu

SUBMITTER: Budzak S 

PROVIDER: S-EPMC5729545 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature