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Arunachalam Lakshmi Stanley Walker Bernard J. McClelland James H. Calderwood 《Journal of Molecular Structure》1982
The potential function for internal rotation of the aldehyde group in the orthometa- and para-fluorobenzaldehydes is calculated by CNDO/2, INDO and STO/6G methods, assuming invariant bond lengths. The INDO and STO/6G calculations indicate the equilibrium geometry to be essentially planar and the barrier to internal rotation to be the potential energy of the molecule when the plane of the aldehyde group is perpendicular to the ring plane; CNDO/2 leads to different conclusions, however. Relative stabilities of O-cis and O-trans rotamers of the planar configuration are discussed. Comparisons are made with the V barriers and the enthalpies of activation as determined by the dielectric absorption method using a matrix technique. 相似文献
85.
An ultraviolet absorption technique is developed for studying molecules cooled in a supersonic expansion. In this experiment, the temperature-dependent contribution to the diffuseness of electronically excited states is reduced for CS2 and butadiene. The broadness of the spectral features of the butadiene 1B1u state is independent of temperature 相似文献
86.
Linda J. Santry Raymond A. Poirier Robert A. McClelland Imre G. Csizmadia 《Theoretical chemistry accounts》1984,65(2):139-149
Ab initio calculations were performed on 2-hydroxy-1,3-oxathiolane: and the two products of its breakdown: Complete geometry optimizations were performed at minimal (STO-3G) and split-valence (3-21G) basis set levels. In addition, a single point calculation was performed at 6-31G* level withd orbitals added on sulfur only. The conformation of the oxathiolane intermediate and its stability relative to the breakdown products was investigated. The STO-3G basis set gave an envelope form while 3-21G gave the twist form of the five-membered ring as the most stable. For all three basis sets the ester product was more stable than thioester. 相似文献
87.
Laser cooling on weak transitions is a useful technique for reaching ultracold temperatures in atoms with multiple valence electrons. However, for strongly magnetic atoms a conventional narrow-line magneto-optical trap (MOT) is destabilized by competition between optical and magnetic forces. We overcome this difficulty in Er by developing an unusual narrow-line MOT that balances optical and magnetic forces using laser light tuned to the blue side of a narrow (8 kHz) transition. The trap population is spin polarized with temperatures reaching below 2 muK. Our results constitute an alternative method for laser cooling on weak transitions, applicable to rare-earth-metal and metastable alkaline earth elements. 相似文献
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谈谈量子力学中的状态叠加原理 总被引:1,自引:1,他引:0
以对话的形式,介绍并评论了布洛欣采夫、狄拉克以及朗道和栗弗席茨关于状态叠加原理的不同表述. 相似文献