物理化学学报 >> 1986, Vol. 2 >> Issue (03): 271-277.doi: 10.3866/PKU.WHXB19860313

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核磁共振偶合常数1JCH的计算

王家振; 曹小平; 廖沐真   

  1. 清华大学化学与化学工程系
  • 收稿日期:1985-07-29 修回日期:1986-01-04 发布日期:1986-06-15

A CALCULATION OF NMR COUPLING CONSTANTS 1JCH

Wang Jiazhen; Cao Xiaoping; Liao Muzhen   

  1. Department of Chemistry and Chemical Engineering Tsinghua University
  • Received:1985-07-29 Revised:1986-01-04 Published:1986-06-15

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摘要： 借助非正交定域分子轨道(简称为LMO)及其伴基所构成的单位算子, 得到以LMO为基计算NMR偶合常数的二级微扰理论公式, 并计算了CH_4、C_2H_4、C_2H_2分子碳原子和氢原子核上的电荷密度及NMR偶合常数~1J_(CH)。计算结果表明, ~1J_(CH)主要由定域于碳原子和氢原子化学键区域的成键与反键LMO所决定, 并与LMO在碳原子和氢原子核上的电荷密度乘积成比例。

Abstract: A formula with second-order perturbation correction is obtained for the calculation NMR coupling constants by means of the unit operator consisting of non-orthogonal LMO and adjoint basis sets The electron densities at the carbon and hydrogen nucleus and the NMR coupling constants ~1J_(CH) for the CH_4, C_2H_4 and C_2H_2 were evalnated respectively. It has been shown that ~1J_(CH) is principally determined by bonding and anti-bonding LMO of the C-H bond and approximately proportional to the product of electron density at the carbon and hydrogen nucleus.