STRUCTURES AND STABILITIES OF THE DIMER DICATIONS OF 1ST-ROW AND 2ND-ROW HYDRIDES
STRUCTURES AND STABILITIES OF THE DIMER DICATIONS OF 1ST-ROW AND 2ND-ROW HYDRIDES
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DOI：
10.1021/ja00195a014
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发表时间：
1989-06-21
影响因子：
15
通讯作者：
RADOM, L
中科院分区：
文献类型：
--
作者：
GILL, PMW;RADOM, L
用从头算分子轨道理论系统地研究了He22+、H3NNH32+、H200H22+、HFFH2+、NE22+、H3PPH32+、H2SSH22+、HC1C1H2+和Ar22+的第一和第二排二聚体结构。虽然所有的九个体系都是热力学不稳定的，对称碎裂成两个单中心，但预测除了HFFH2+，NE22+和Ar22+之外的所有二聚体都存在抑制这种碎裂的势垒。特别是，肼和双膦配位在对称碎裂和去质子化方面被发现是非常稳定的。二聚体(A22+)的平衡AA键长都明显短于相应的(半键)单离子(A2*+)，但断裂势垒通常较小。发现二聚体的平衡结构与它们的等电子、等结构、中性的平衡结构非常相似。强调了最近引入的参数在理解所有九个判据的稳定性和碎裂过程中的作用。
Ab initio molecular orbital theory has been used in a systematic study of the first-and second-row dimer dicationsHe22+, H3NNH32+, H200H22+, HFFH2+, Ne22+, H3PPH32+, H2SSH22+, HC1C1H2+, and Ar22+. Although all nine systems are thermodynamically unstable with respect tosymmetric fragmentation into two monocations, potential energy barriers inhibiting such fragmentations are predicted to exist for all of the dimers except HFFH2+, Ne22+, and Ar22+. In particular, the hydrazinium and diphosphinium dications are found tobe very stable kinetically with respect to both symmetric fragmentation and deprotonation. The equilibrium AA bond lengths in the dimer dications (A22+) are all significantly shorter than in the corresponding (hemibonded) monocations (A2*+), but the fragmentation barriers are usually smaller. The equilibrium structures of the dimer dications are found to be very similar to those of their isoelectronic, isostructural, neutral counterparts. The usefulness of the recently introduced parameter in understanding the stabilities and fragmentation processes of all nine dications is emphasized.