Dual vibration configuration interaction (DVCI). An efficient factorization of molecular Hamiltonian for high performance infrared spectrum computation

TL;DR

The paper introduces DVCI, a novel method for high-precision infrared spectrum calculations that efficiently targets specific vibrational states by innovative Hamiltonian factorization and a minimal-memory eigensolver.

Contribution

It presents a new factorization of the molecular Hamiltonian using duality and second quantization, enabling efficient and precise vibrational spectrum computations with reduced memory usage.

Findings

Rapid convergence to variational limit of targeted eigenpairs

Reduced memory requirements for spectrum calculations

Effective basis set augmentation from residual vector components

Abstract

Here is presented an original program based on molecular Schrodinger equations. It is dedicated to target specific states of infrared vibrational spectrum in a very precise way with a minimal usage of memory. An eigensolver combined with a new probing technique accumulates information along the iterations so that desired eigenpairs rapidly tend towards the variational limit. Basis set is augmented from the maximal components of residual vectors that usually require the construction of a big matrix block that here is bypassed with a new factorisation of the Hamiltonian. The latest borrows the mathematical concept of duality and the second quantization formalism of quantum theory.