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Analytical derivatives of the individual state energies in ensemble density functional theory method. I. General formalism
- Source :
- The Journal of Chemical Physics. 147:034113
- Publication Year :
- 2017
- Publisher :
- AIP Publishing, 2017.
-
Abstract
- The state-averaged (SA) spin restricted ensemble referenced Kohn-Sham (REKS) method and its state interaction (SI) extension, SI-SA-REKS, enable one to describe correctly the shape of the ground and excited potential energy surfaces of molecules undergoing bond breaking/bond formation reactions including features such as conical intersections crucial for theoretical modeling of non-adiabatic reactions. Until recently, application of the SA-REKS and SI-SA-REKS methods to modeling the dynamics of such reactions was obstructed due to the lack of the analytical energy derivatives. In this work, the analytical derivatives of the individual SA-REKS and SI-SA-REKS energies are derived. The final analytic gradient expressions are formulated entirely in terms of traces of matrix products and are presented in the form convenient for implementation in the traditional quantum chemical codes employing basis set expansions of the molecular orbitals. The implementation and benchmarking of the derived formalism will be described in a subsequent article of this series.
- Subjects :
- 010304 chemical physics
Chemistry
General Physics and Astronomy
Conical surface
010402 general chemistry
01 natural sciences
Potential energy
Quantum chemistry
0104 chemical sciences
Quantum mechanics
Excited state
0103 physical sciences
Molecule
Density functional theory
Molecular orbital
Statistical physics
Physical and Theoretical Chemistry
Basis set
Subjects
Details
- ISSN :
- 10897690 and 00219606
- Volume :
- 147
- Database :
- OpenAIRE
- Journal :
- The Journal of Chemical Physics
- Accession number :
- edsair.doi.dedup.....ea741b3b22d2fa637e121bc3b0aca965
- Full Text :
- https://doi.org/10.1063/1.4994542