Ultrafast transient vibrational action spectroscopy of cryogenically cooled ions

Ultrafast transient vibrational action spectra of cryogenically cooled Re(CO)(3)(CH3CN)(3)(+) ions are presented. Nonlinear spectra were collected in the time domain by monitoring the photodissociation of a weakly bound N-2 messenger tag as a function of delay times and phases between a set of three infrared pulses. Frequency-resolved spectra in the carbonyl stretch region show relatively strong bleaching signals that oscillate at the difference frequency between the two observed vibrational features as a function of the pump-probe waiting time. This observation is consistent with the presence of nonlinear pathways resulting from underlying cross-peak signals between the coupled symmetric-asymmetric C & EQUIV;O stretch pair. The successful demonstration of frequency-resolved ultrafast transient vibrational action spectroscopy of dilute molecular ion ensembles provides an exciting, new framework for the study of molecular dynamics in isolated, complex molecular ion systems.

Automated summary

This study presents ultrafast transient vibrational action spectra of cryogenically cooled Re(CO)(3)(CH3CN)(3)(+) ions. Nonlinear spectra were collected in the time domain by monitoring the photodissociation of a weakly bound N-2 messenger tag. In the carbonyl stretch region, frequency-resolved spectra show relatively strong bleaching signals that oscillate at the difference frequency between the two observed vibrational features. This observation suggests the presence of nonlinear pathways resulting from underlying cross-peak signals between the coupled symmetric-asymmetric C & EQUIV;O stretch pair.