摘要
The size consistency of the second and third order energies of the multireference perturbation theory(Chen F, Davidson E, Iwata S. Int J Quant Chem, 2002, 86: 256) is investigated theoretically with a su-per-molecular model composed of N-hydrogen molecules separated by a large distance. It is found that the two perturbation series corresponding to two Hamiltonian partitions are not size consistent at the second and third order. However, two size consistent forms are suggested for two Hamiltonian parti-tions at the second order, if some approximations to the denominators of the original second order energies are assumed.
The size consistency of the second and third order energies of the multireference perturbation theory (Chen F, Davidson E, Iwata S. Int J Quant Chem, 2002, 86: 256) is investigated theoretically with a super-molecular model composed of N-hydrogen molecules separated by a large distance. It is found that the two perturbation series corresponding to two Hamiltonian partitions are not size consistent at the second and third order. However, two size consistent forms are suggested for two Hamiltonian partitions at the second order, if some approximations to the denominators of the original second order energies are assumed.
基金
Supported by the National Natural Science Foundation of China (Grant No. 20473011)
the University of Science and Technology Beijing (Grant No. 00007414)
the Ministry of Education of China (Grant No. 11140036)
