Four FeCO states with 3d4s and 3d3d electrons spinpaired or spinunpaired were examined to investigate the influences of pairing versus unpairing mechanisms upon the bonding and interaction in FeCO.The calculation resu...Four FeCO states with 3d4s and 3d3d electrons spinpaired or spinunpaired were examined to investigate the influences of pairing versus unpairing mechanisms upon the bonding and interaction in FeCO.The calculation results show that the FeCO bonding and interaction are determined by a balance between the bonding stabilization and the exchange stabilization with 3d4s electron spinpairing or without it.The 3d3d electron spinpairing versus unpairing has a surprised effect on the FeCO bonding properties even though the 3d orbitals are usually considered as non bonding ones.展开更多
This paper presents an efficient algorithm for energy gradients in valence bond self-consistent field(VBSCF) method with non-orthogonal orbitals.The frozen core approximation method is extended to the case of non-orth...This paper presents an efficient algorithm for energy gradients in valence bond self-consistent field(VBSCF) method with non-orthogonal orbitals.The frozen core approximation method is extended to the case of non-orthogonal orbitals.The expressions for the total energy and its gradients are presented by introducing auxiliary orbitals,where inactive orbitals are orthogonal,while active orbitals are non-orthogonal themselves but orthogonal to inactive orbitals.It is shown that our new algorithm has a low scaling of(Na+1)m4,where Na and m are the numbers of the active orbitals and basis functions,respectively,and is more efficient than the existing VBSCF algorithms.展开更多
文摘Four FeCO states with 3d4s and 3d3d electrons spinpaired or spinunpaired were examined to investigate the influences of pairing versus unpairing mechanisms upon the bonding and interaction in FeCO.The calculation results show that the FeCO bonding and interaction are determined by a balance between the bonding stabilization and the exchange stabilization with 3d4s electron spinpairing or without it.The 3d3d electron spinpairing versus unpairing has a surprised effect on the FeCO bonding properties even though the 3d orbitals are usually considered as non bonding ones.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20533020, 20873106)the National Basic Research Program of China (Grant No. 204CB719902)
文摘This paper presents an efficient algorithm for energy gradients in valence bond self-consistent field(VBSCF) method with non-orthogonal orbitals.The frozen core approximation method is extended to the case of non-orthogonal orbitals.The expressions for the total energy and its gradients are presented by introducing auxiliary orbitals,where inactive orbitals are orthogonal,while active orbitals are non-orthogonal themselves but orthogonal to inactive orbitals.It is shown that our new algorithm has a low scaling of(Na+1)m4,where Na and m are the numbers of the active orbitals and basis functions,respectively,and is more efficient than the existing VBSCF algorithms.
