论文部分内容阅读
半经验分子轨道法在量子化学中十分重要,是化学工作者的有力工具。它以自洽场分子轨道理论为基础,是一种经验地选取参数与必要的量子化学计算巧妙相结合的方法。它不同于经验的分子轨道法,在经验法中,主要根据经验选择相互作用能矩阵元的数值,计算简单,但精度差;它不同于从头计算法,从头计算法是一种以自洽场分子轨道理论为基础的非经验法,计算工作量大。半经验分子轨道法的优点是计算工作量较从头计算法少得多,而且,不但可计算相对能量,也可计算绝对能量。
Semi-empirical molecular orbital method in quantum chemistry is very important, is a powerful tool for chemical workers. It is based on self-consistent field orbital theory and is a combination of empirically chosen parameters and the necessary quantum chemistry calculations. It is different from the empirical molecular orbital method. In the empirical method, the matrix element values of interaction can be chosen mainly based on experience. The calculation is simple, but the precision is poor. It is different from ab initio method, Molecular orbital theory as the basis of the non-empirical method, computational workload. The advantage of semi-empirical molecular orbital method is that the computational workload is much less than that of the first calculation, and not only the relative energy but also the absolute energy can be calculated.