A comparison of spin-flip TDDFT-based conical intersection approaches with XMS-CASPT2

Winslow, M, Cross, WB ORCID: https://orcid.org/0000-0001-6277-400X and Robinson, D ORCID: https://orcid.org/0000-0003-2760-7163, 2020. A comparison of spin-flip TDDFT-based conical intersection approaches with XMS-CASPT2. Journal of Chemical Theory and Computation, 16 (5), pp. 3253-3263. ISSN 1549-9618

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Abstract

Determining conical intersection geometries is of key importance to understanding the photochemical reactivity of molecules. While many small to medium-sized molecules can be treated accurately using multireference approaches, larger molecules require a less computationally demanding approach. In this work, minimum energy crossing point conical intersection geometries for a series of molecules has been studied using spin-flip TDDFT (SF-TDDFT), within the Tamm-Dancoff Approximaton, both with and without explicit calculation of non-adiabatic coupling terms, and compared with both XMS-CASPT2 and CASSCF calculated geometries. The less-computationally demanding algorithms, which do not require explicit calculation of the non-adiabatic coupling terms, generally fare well with the XMS-CASPT2 reference structures, while the relative energetics are only reasonably replicated with the MECP structure calculated with the BHHLYP functional and full non-adiabatic coupling terms. We also demonstrate that, occasionally, CASSCF structures deviate quantitatively from the XMS-CASPT2 structures, showing the importance of including dynamical correlation.

Item Type:	Journal article
Publication Title:	Journal of Chemical Theory and Computation
Creators:	Winslow, M., Cross, W.B. and Robinson, D.
Publisher:	American Chemical Society
Date:	12 May 2020
Volume:	16
Number:	5
ISSN:	1549-9618
Identifiers:	Number Type 10.1021/acs.jctc.9b00917 DOI 1317542 Other
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	22 Apr 2020 10:16
Last Modified:	31 May 2021 15:04
URI:	https://irep.ntu.ac.uk/id/eprint/39716

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