【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CH₄、C₂H₄、C₂H₂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。更多还原

【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 CH₄, C₂H₄ and C₂H₂ 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.更多还原