Heitler-London近似下自旋空间中H_2分子的能量本征值

Elementary introduction to eigenvalue of energy of H_2 molecule in spin space under Heitler-London approximate

对于H2分子系统可采用Heitler-London近似及"分子轨道近似"进行计算.虽然两种近似得出相同的总能量以及相同的轨道波函数,但是总能量在单电子能量、库仑能量和交换能量三者之间的相对分布不相同.由"分子轨道近似"所得的交换积分总为正值,而Heitler-London近似所得的交换积分可正可负更接近实际.因此对于H2分子模型,Heitler-London近似比"分子轨道近似"更为准确一些.所以采用Heitler-London近似下在自旋空间中利用自旋-自旋相互作用的自旋置换算符讨论了H2分子的能量本征值.

We use molecular orbital approximation and HeitlerLondon approximation to calculate the data of H2 molecule.Though two ways of approximating get the same orbital wave function and total energy,the exchange energy,Coulomb energy and oneelectron energy,they compose the total energy,take different proportions in the two methods.Because exchange integral calculated by molecular ordbital approximation is always positive and HeitlerLondon approximation can get more accurate exchange integral,so that HeitlerLondon approximation is better than molecular orbital approximation.Under HeitlerLondon approximation we discuss the eigenvalue of energy of Hydrogen molecule by using spin permutation operator of spinspin interaction in the spin space.