Symmetry-adapted formulation of the G-particle-hole hypervirial equation method

• Autores: Massaccesi, Gustavo E.; Alcoba, Diego Ricardo; Oña, Ofelia Beatriz
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Química; Matemática; Correlation matrix; G-particle-hole matrix; Electronic correlation effects; Hypervirial of the G-particle-hole operator; Point group symmetry
• Institución: Universidad Nacional de La Plata

Highly accurate 2-body reduced density matrices of atoms and molecules have been directly determined without calculation of their wave functions with the use of the G-particle-hole hypervirial (GHV) equation method (Alcoba et al. in Int. J. Quantum Chem. 109:3178, 2009). Very recently, the computational efficiency of the GHV method has been significantly enhanced through the use of sum factorization and matrix-matrix multiplication (Alcoba et al. in Int. J. Quantum Chem 111:937, 2011). In this paper, a detailed analysis of the matrix contractions involved in GHV calculations is carried out. The analysis leads to a convenient strategy for exploiting point group symmetry, by which the computational efficiency of the GHV method is further improved. Implementation of the symmetry-adapted formulation of the method is reported. Computer timings and hardware requirements are illustrated for several representative chemical systems. Finally, the method is applied to the well-known challenging calculation of the torsional potential in ethylene.
Facultad de Ciencias Exactas
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas