Applying Monte Carlo configuration interaction to transition metal dimers: exploring the balance between static and dynamic correlation

TL;DR

This paper applies Monte Carlo configuration interaction to transition metal dimers, analyzing their potential energy curves and spectroscopic properties to better understand static and dynamic electron correlation effects.

Contribution

It introduces the use of MCCI for transition metal dimers, quantifies multireference character, and estimates important orbitals, providing new insights into their electronic structure.

Findings

MCCI accurately reproduces potential curves for transition metal dimers.

The multireference nature of wavefunctions is effectively quantified.

Relativistic effects are partially included and analyzed for molybdenum dimer.

Abstract

We calculate potential curves for transition metal dimers using Monte Carlo configuration interaction (MCCI). These results, and their associated spectroscopic values, are compared with experimental and computational studies. The multireference nature of the MCCI wavefunction is quantified and we estimate the important orbitals. We initially consider the ground state of the chromium dimer. Next we calculate potential curves for Sc$_{2}$ where we contrast the lowest triplet and quintet states. We look at the molybdenum dimer where we compare non-relativistic results with the partial inclusion of relativistic effects via effective core potentials, and report results for scandium nickel.