Demos.MolVibration.Cl-NH3

The vibrational dynamics following instantaneous photoelectron detachment of the Cl⁻···NH₃ complex is studied. Depending on the wavelength chosen, a wavepacket can be 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.

The reduced, two-dimensional model of the complex employs only the NH₂ - H (R₁) and H - Cl (R₂) distance assuming a planar C_2v structure. It can be seen in the animations below, that the vibrational dynamics is strongly determined by the kinetic coupling of these two degrees of freedom which is typical for a heavy-light-heavy linear triatomic system. Essentially, the light H atom rattles inside the cage provided by the heavy NH₂ and Cl moiety with only little energy transfer to the latter ones. Potentials adapted from our work on a nonadiabatic chemical reaction.

Ground state of the neutral complex: neutral

• Animation of evolving wavepacket
• Input data file
• Tabulated potential
• Logfile output

Electronically excited state of the neutral complex: charge transfer

• Animation of evolving wavepacket
• Input data file
• Tabulated potential
• Logfile output

Coupled dynamics: Nonadiabatic chemical reaction

The proton transfer reaction is observed if the nonadiabatic coupling between ground and excited state of the neutral complex is taken into account. This gives rise to strong nonadiabatic transitions from the excited (charge transfer) state to the ground (neutral) state. The complex decays into NH₂ + HCl, both in their electronic ground states. see our article in Phys. Rev. Lett. 93, 048301 (2004).