Click the figure to run AVI animation
WavePacket is a is a MatLab program package for numerical simulation of quantum-mechanical wavepacket dynamics for distinguishable particles. It can be used to solve (one or several coupled) time-independent or time-dependent linear Schrödinger equations. Optionally accounting for the interaction with external electric fields within the semiclassical dipole approximation, WavePacket is especially suited to simulate modern experiments using ultrashort laser pulses on ps/fs/as timescales. Thus it can be used as a flexible tool for many simulation tasks in photoinduced physics, chemistry, and in related fields. The extended graphical capabilities allow visualization of wavepacket dynamics 'on the fly', including Wigner transforms in classical phase space. WavePacket is especially suitable for teaching of quantum mechanics in physics, chemistry, and scientific computing.
Free downloads of (current and previous versions) of the Matlab source codes as well as documentation and instructions are available from the WavePacket website at the SourceForge platform. The installation procedure is simple, and even unexperienced users should be able to pursue quantum simulations within short time. Many worked-out examples illustrating the use of the WavePacket simulation tools are available. Along with complete input and output files as well as animated graphics, they serve to illustrate the capabilities of the WavePacket program package, as detailed in the following.
The first set of examples serves to illustrate a number of textbook examples where analytical solutions are known for the most part. However, the time-dependent picture of quantum mechanics provides a completely new point of view, and many intriguing features can be found in the animated graphics. Read more ...
Although the Born-Oppenheimer (adiabatic) approximation provides the most intuitive picture of molecular dynamics in terms of densities/wavepackets moving along uncoupled(!) potential energy surfaces, many chemical reactions, most notably in photochemistry and photobiology are governed by non-adiabatic processes, i. e., they involve nuclear dynamics on (at least!) two different electronic states. This breakdown of the adiabatic approximation occurs most frequently where spectral gaps between electronic eigenstates become sufficiently small or vanish altogether. Prominent examples are (avoided) crossings of potential energy curves (in one dimension) and seams or conical intersections (in two or more dimensions). Read more ...
In recent years, there has been a great deal of effort on the manipulation of the dynamics of quantum systems. In most cases, these approaches make use of the interaction of external electromagnetic fields with various molecular systems through their dipoles or polarizabilities. On the experimental side, the advent of very intense and short, tailored laser pulses has made a direct control of physical, chemical, and even biological systems possible, typically on timescales of picoseconds to femtoseconds. In most of this field, molecular simulations are indispensible, both for interpreting existing experiments and for the prediction of future ones. Read more ...
Last update: 19-Dec-2008 15:45
Burkhard Schmidt
