哌嗪二酮的气相HeI光电子能谱及其量化计算

GAS PHASE ULTRAVIOLET PHOTOELCTRON SPECTROSCOPY AND THEORETICAL CALCULATIONS OF PIPERAZINE-2,5-DIONE MOLECULE

给出了哌嗪二酮的气相HeI 紫外光电子能谱(UPS),并进行了化合物分子的HAM/3,MNDO,MINDO/3,INDO,CNDO/2和EHMO 等量子化学计算研究.UPS谱低电离能(<11.00eV)区的四重峰被指认为分子体系中氧-氧,氮-氮原子孤对轨道间的通过键相互作用导致的分裂峰.表明HAM/3和MNDO 计算法是预指该化合物实验电离能正确次序、轨道对称性类型以及通过键相互作用导致分裂大小的较好方法.

A complete gas phase ultraviolet photoelectron spectrum(UPS)and HAM/3,MNDO,EHMO,MINDO/3,INDO as well as CNDO/2 molecular orbital calculations of pipera-zine-2,5-dione molecule are present in this paper.The tetra-multiple splitting peaksof the first band of piperazine-2,5-dione UPS spectrum have been assigned as thethrough-bond interactive aplittings which come from the oxygen and oxygen lone pairs,nitrogen and nitrogen lone pairs,respectively.And it has also shown that HAM/3and MNDO calculations are better methods to predict the correct order of experimen-tal ionization energies(I(?)),orbital symmetry and the splitting spacing ofthrough-bond and through-space interactions in-this molecule.MNDO optimumgeometry of the molecule results in molecular plane conjugation and the reduction ofthroughbond splitting spacing.