Quantum molecular dynamics: propagating wavepackets and density operators using the multiconfiguration time-dependent Hartree method

Abstract.

 Quantum molecular dynamics describes the time-evolution of a chemical system at the atomic level by directly solving the Schrödinger equation. Time-dependent methods, exemplified by wavepacket propagation, are by now developed to a point where they provide an important insight into the mechanism of many fundamental processes. Of these methods, the most versatile and efficient is probably the multi-configuration time-dependent Hartree (MCTDH) method. The form of the wavefunction used leads to a particularly compact description of the system, and it is possible to run either qualitative, cheap, or accurate, expensive calculations within the same framework. MCTDH has now shown that it is able to treat systems much larger than other wavepacket propagation methods, and benchmark calculations on systems with up to 24 degrees of freedom have been made. In contrast, standard methods can rarely treat more than 4–6 degrees of freedom. In the following, we review the basic theory of MCTDH. Recent advances are included, such as the development of the method for treating the time-evolution of density operators.