Demos.MolVibration.Main

WavePacket demo examples: Molecular vibration

In this section the vibrational dynamics of small molecules is investigated. To this end, a few examples from our recent work are used to illustrate the behaviour of 'real life' molecules. In contrast to the model cases in other parts of the Guided Tour, the potential energy curves/surfaces are obtained on a pointwise basis from electronic structure calculations; in order to utilize them in WavePacket, spline interpolation has to be carried out.

OH radical

The example of the OH radical is often considered as a one-dimensional model of water vibrational dynamics, described in terms of the Morse oscillator introduced previously. We are investigating here the use of ultra-short intense infrared light pulses to excite the OH radical in an effective and state-selective manner. Emphasis is on the population of highly excited states using one- or multi-photon processes. Learn more ...

HF molecule

In many-level systems with different energy gaps, efficient population of highly excited states can be obtained by chirping the laser pulse, i.e., changing the central frequency as a function of time. The intuitive picture here is that the laser is always resonant with respect to some transition, leading to subsequent population of higher and higher excited states. This is demonstrated here for the vibrational excitation of an HF molecule, using chirped infrared light pulses. Learn more ...

H₃⁺ cation

The triatomic cation H₃⁺ provides a test case for the implementation of a general kinetic energy operator in Jacobi coordinates. We use a modified version of the Chebyshev propagator in imaginary time to obtain the lowest few eigenstates of the molecule. It turns out that the convergence deteriorates rapidly with increasing quantum numbers. Learn more ...

Cl⁻···NH₃ complex

The vibrational dynamics following instantaneous photoelectron detachment of the Cl⁻···NH₃ complex is studied. Depending on the wavelength chosen, a wavepacket can created by vertically promoting the vibrational wavepacket of the anionic complex either to the ground or excited (charge transfer!) state of the neutral complex. The corresponding potential energy surfaces are taken from high level quantum chemical calculations. Learn more ...