Characterizing strong-field-induced molecular dynamics employing time-energy-frequency analysis of vibrational wave packet motion*

We employ time-resolved 3D momentum imaging combined with channel- and energy-resolved Fourier spectroscopy to study pathways of strong-field ionization and fragmentation of CH$_{\mathrm{3}}$I, and to map vibrational wave packet dynamics in the intermediate neutral and cationic states. Analyzing the delay-dependent signals of bound parent ions as well as CH$_{\mathrm{3}}^{\mathrm{+}}$ and I$^{\mathrm{+n}}$ ($n=$1,2,3) ionic fragments recorded in a pump-probe measurement with two 25 fs, 780 nm laser pulses, we disentangle different reaction channels based on the measured charge states, kinetic energies and angular distributions. Energy-resolved Fourier spectra and the absolute phases of vibrational wave packets extracted from these delay-dependent measurements provide specific information about the intermediate states contributing to particular reaction pathways.