Theoretical study of photoisomerisation processes involving a conical intersection

该项目的目的是研究涉及锥形交叉的光异构化过程。为此，必须解决几个问题。(i)当我们处理相对较大的分子时（比如说9到30个自由度），使用模型哈密顿量是合适的。这种方法的一个众所周知的例子是振动耦合哈密顿量[1]。然而，该模型仅适用于小振幅运动，而异构化涉及至少几个坐标的大振幅运动。因此，我们的目标是开发一个模型哈密顿曲线坐标，这是更一般，更适合我们的目的。(ii)在曲线坐标系中，动能算符的推导是一项繁琐而困难的工作。这项工作将自动化。最终的解决方案将是一个程序，它为MCTDH程序编写一个所谓的操作符文件。(iii)必须进一步开发MCTDH程序，使其能够解析和处理自动生成的操作员文件。此外，由于要研究相对较大的分子，因此需要改进MCTDH在这些大系统上的性能。(iv)模拟光诱导异构化过程的应用计算必须使用海德堡MCTDH软件包进行。

The aim of the project is to study photoisomerisation processes which involve conical intersections. For this several problems have to be solved.(i) As one is dealing with comparatively large molecules (9 to 30 degrees of freedom, say) it is appropriate to use a model Hamiltonian. A well known example of such an approach is the vibronic coupling Hamiltonian [1]. However, this model is applicable for small amplitude motion only, whereas isomerisation involves large amplitude motion of at least a few coordinates. Hence it is our aim to develop a model Hamiltonian in curvilinear coordinates which is more general and more suitable for our purposes.(ii) The derivation of the kinetic energy operator in curvilinear coordinates is a cumbersome and difficult task. This task shall be automatised. The ultimate solution would be a program which writes a so called operator file for the MCTDH program.(iii) The MCTDH program has to be further developed such that it can parse and process the automatically generated operator file. Furthermore, as comparatively large molecules are to be investigated, one needs to improve the performance of MCTDH on these large systems.(iv) The application calculations simulating the photo-induced isomerisation processes have to be performed using the Heidelberg MCTDH package.