Accelerating an iterative eigensolver for nuclear structure configuration interaction calculations on GPUs using OpenACC

Multireference configuration interaction calculations are carried out for ground and excited states of trichloromethanol to investigate two important photofragmentation processes relevant to atmospheric chemistry. For CCl3OH five low-lying excited states in the energy range between 6.1 and 7.1 eV are found to be highly repulsive for C-Cl elongation leading to Cl2COH (X2A') and Cl (X2P). Photodissociation along C-O cleavage resulting in Cl3C (X2A') and OH (X2Π) has to overcome a barrier of about 0.8 eV (13A'', 11A'') and 1.2 eV (13A') because the low-lying excited states 11A'', 13A' and 13A'' become repulsive only after elongating the C-O bond by about 0.3 Å.

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Multireference Configuration Interaction Calculations on Cr2: Passing the One Billion Limit in MRCI/MRACPF Calculations

The Journal of Physical Chemistry A ◽

10.1021/jp982648s ◽

1999 ◽

Vol 103 (1) ◽

pp. 152-155 ◽

Cited By ~ 55

Author(s):

Holger Dachsel ◽

Robert J. Harrison ◽

David A. Dixon

Keyword(s):

Configuration Interaction ◽

The One ◽

Configuration Interaction Calculations

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Configuration interaction calculations of the helium pair potential including CI superposition corrections

Molecular Physics ◽

10.1080/00268977900101111 ◽

1979 ◽

Vol 37 (5) ◽

pp. 1529-1541 ◽

Cited By ~ 28

Author(s):

Peter D. Dacre

Keyword(s):

Configuration Interaction ◽

Pair Potential ◽

Configuration Interaction Calculations

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Modification of HAM/3 excitation energies for ΠΠ* transitions of linear molecules

Canadian Journal of Chemistry ◽

10.1139/v80-270 ◽

1980 ◽

Vol 58 (16) ◽

pp. 1687-1690 ◽

Cited By ~ 8

Author(s):

Delano P. Chong

Keyword(s):

Excitation Energy ◽

Explicit Expression ◽

Excited States ◽

Configuration Interaction ◽

Excitation Energies ◽

Carbon Suboxide ◽

Numerical Examples ◽

Energy Correction ◽

Linear Molecules ◽

Configuration Interaction Calculations

The excitation energies calculated by the HAM/3 procedure for ΠΠ* transitions in linear molecules can be internally inconsistent by as much as ± 0.6 eV. In the recent study by Åsbrink etal., the problem was avoided by adopting Recknagel's expressions and requiring the proper average ΠΠ* excitation energy. In this paper, we trace the small inconsistency back to its origin in HAM/3 theory and derive the analytical expression for the energy correction as well as Recknagel's formulas. Numerical examples studied include all seven linear molecules investigated by Åsbrink etal. The explicit expression for the correction enables us to perform meaningful configuration-interaction calculations on the excited states, as illustrated by the carbon suboxide molecule.

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