Two-photon absorption cross sections within equation-of-motion coupled-cluster formalism using resolution-of-the-identity and Cholesky decomposition representations: Theory, implementation, and benchmarks

Journal Article · Sat Feb 14 00:00:00 EST 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4907715· OSTI ID:22416102

Nanda, Kaushik D.; Krylov, Anna I. ^[1]

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1. Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482 (United States)

The equation-of-motion coupled-cluster (EOM-CC) methods provide a robust description of electronically excited states and their properties. Here, we present a formalism for two-photon absorption (2PA) cross sections for the equation-of-motion for excitation energies CC with single and double substitutions (EOM-CC for electronically excited states with single and double substitutions) wave functions. Rather than the response theory formulation, we employ the expectation-value approach which is commonly used within EOM-CC, configuration interaction, and algebraic diagrammatic construction frameworks. In addition to canonical implementation, we also exploit resolution-of-the-identity (RI) and Cholesky decomposition (CD) for the electron-repulsion integrals to reduce memory requirements and to increase parallel efficiency. The new methods are benchmarked against the CCSD and CC3 response theories for several small molecules. We found that the expectation-value 2PA cross sections are within 5% from the quadratic response CCSD values. The RI and CD approximations lead to small errors relative to the canonical implementation (less than 4%) while affording computational savings. RI/CD successfully address the well-known issue of large basis set requirements for 2PA cross sections calculations. The capabilities of the new code are illustrated by calculations of the 2PA cross sections for model chromophores of the photoactive yellow and green fluorescent proteins.

• OSTI ID: 22416102
• Journal Information: Journal of Chemical Physics, Vol. 142, Issue 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
APPROXIMATIONS
BENCHMARKS
CONFIGURATION INTERACTION
CROSS SECTIONS
DECOMPOSITION
ELECTRONS
EQUATIONS OF MOTION
EXCITATION
EXCITED STATES
EXPECTATION VALUE
FLUORESCENCE
IMPLEMENTATION
INTEGRALS
MOLECULES
PHOTONS
PROTEINS
RESOLUTION
WAVE FUNCTIONS