Bonding Analysis of the Shortest Bond between Two Atoms Heavier than Hydrogen and Helium: O22+
Bonding Analysis of the Shortest Bond between Two Atoms Heavier than Hydrogen and Helium: O22+
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比氢和氦重的两个原子之间最短键的成键分析：O22
DOI：
10.1021/acs.jpca.9b11117
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发表时间：
2020-02-13
影响因子：
2.9
通讯作者：
Frenking, Gernot
中科院分区：
文献类型：
--
作者：
Fu, Mingxing;Pan, Sudip;Frenking, Gernot
对O-2（2+）和N进行了大基集CCSD(T)水平的从头算量子化学计算，并使用BP86泛函进行了DFT计算。化学键的能量分解分析表明，与等电子N-2相比，O-2（2+）中的键较短是由于离子中的泡利排斥较弱，这过度补偿了N-2中起作用的吸引相互作用的减弱。在N-2的平衡距离处，O-2（2+）的轨道（共价键）键比N-2弱，中性双原子体系中的吸引库仑相互作用在此过程中变为排斥作用，但由于O-2（2+）轨道的收缩导致泡利斥力的减弱，抵消了这些作用力，导致键的缩短。结果还表明，键解离能并不是键强度的可靠指标，而是由（局部）力常数给出的。
Quantum chemical calculations using ab initio methods at the CCSD(T) level with large basis sets and DFT calculations using the BP86 functional have been carried out for O-2(2+) and N An energy decomposition analysis of the chemical bonds suggests that the shorter bond in O-2(2+) compared with isoelectronic N-2 is due to the weaker Pauli repulsion in the dication, which overcompensates the weakening of attractive interactions that are operative in N-2. At the equilibrium distance of N-2, the orbital (covalent) bonding in O-2(2+) is weaker than in N-2, and the attractive Coulomb interactions in the neutral diatomic system become repulsive in the dication, but the weakening of the Pauli repulsion caused by the shrinking of the orbitals in O-2(2+) compensates for these forces and leads to a shortening of the bond. The results also show that the bond dissociation energy is not a reliable indicator for the strength of bond, which is more faithfully given by the (local) force constant.