分子光解截面模拟的劈裂算符-傅立叶变换方案

Application of Split Operator-Fourier Transform Scheme to the Calculation of Photodissociation Cross Section

采用含时量子方法中的劈裂算符-傅立叶变换方案研究了IBr分子从初始态X1Σ+(0+)3个振动能级上跃迁到激发态C1Π(1)的光解离吸收截面,研究表明在计算光解总的吸收截面时,各势能面间的耦合对吸收截面峰值基本没有影响,从初始态不同的振动能级跃迁到激发态上光解截面的吸收谱峰值存在振荡现象.在计算中劈裂算符-傅立叶变换方案的时间演化算符的幺正性保证了波函数在传播过程中的规范性.同时,计算时可以根据实际情况选择一定个数的格点,在一定程度上提高了计算效率.

The split operator-Fourier transform scheme in the time-dependent wavepacket dynamics is applied to simulate the photodissociation absorption cross section for IBr molecules in strong fields.The research shows that all potential curves coupling of IBr have no effect on calculating the total photodissociation cross section.In this scheme,the unitary of time evolution operators makes sure that the wave function is normalized in time-space propagation.In addition,the choice of the finite grid points may enhance the calculation efficiency.