STEALING IDEAS FROM ELECTRONIC STRUCTURE THEORY TO IMPROVE VIBRATIONAL CALCULATIONS. PART I - THE HAMILTONIAN

Thorpe, James H.

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Title

STEALING IDEAS FROM ELECTRONIC STRUCTURE THEORY TO IMPROVE VIBRATIONAL CALCULATIONS. PART I - THE HAMILTONIAN

Author(s)

Thorpe, James H.

Issue Date

2023-06-21

Keyword(s)

Theory and Computation

Abstract

The fields of electronic and vibrational structure theory have largely evolved independently over the years. Demonstrative of this is the fact that the electronic structure community has generally embraced coupled-cluster wavefunctions as the gold standard for small, well-behaved systems, while vibrational structure practitioners tend to prefer treatments based on vibrational perturbation theory or vibrational configuration interaction. While this is not surprising — the two fields face dramatically different challenges and goals — one does wonder if ideas from one can be used to improve or inform the other. To this point, Part I of this presentation borrows the concept of normal-ordered strings of creation/annihilation operators from electronic coupled-cluster to develop a new form of the vibrational Hamiltonian which is amenable to vibrational many-body (VMP,VCI,VCC) calculations. This "GEN" Hamiltonian generates greatly simplified equations to be implemented in black-box software, and folds-in higher-order many-body effects into lower-order treatments. The goal is to present these (somewhat complicated) concepts in a way accessible to theorists from both communities, as well as to the broader field of spectroscopists as a whole.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122414

DOI

https://doi.org/10.15278/isms.2023.6975

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