First-Principles Calculation of Laser Crystal Multiplet Levels via Hybridized Density Functional Theory and Configuration Interaction within the OLCAO Method
Abstract
Computation of highly-localized multiplet energy levels of transition metal dopants
is essential to the design of materials such as laser host crystals. A purely first-principles
density functional theory-configuration interaction (DFT-CI) hybrid computational
method has been developed to accurately compute multiplet energy levels for single atoms
of carbon, nitrogen, oxygen, sodium, aluminum, silicon, titanium, and chromium. The
multiplet energy levels have been computed with close experimental agreement in terms
of magnitude and degeneracy, and the method does not depend on empirical information
(i.e. Racah parameters). The computed multiplet energy level results are distributed
according to term symbols, which are then compared to experimentally-observed multiplet
energy levels. The hybrid method consists of analytic computation of two-electron
integrals via the DFT-based orthogonalized linear combination of atomic orbitals
(OLCAO) method, which are subsequently used as input for the CI-based discrete
variational multi-electron (DVME) method to obtain the multiplet energy values.
Development of this hybrid method led to the correction of existing Fortran subroutines in
the previous version of the OLCAO program suite, resulting in increased accuracy in the
computation of optical properties (dielectric function and energy loss function).
Table of Contents
Introduction -- Methods -- Results and discussion -- Multiplet state computation with DFT-CI hybrid method -- Future work -- Appendix A. Mathematical formalism -- Appendix B. Program code
Degree
Ph.D.