Abstract
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 N2 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≡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.
Supplementary materials
Title
Supplementary Materials
Description
Experimental details on ion generation, pulse generation, data acquisition, and data processing. Mass spectrum of Re(CO)3(CH3CN)3+∙(N2)n (Fig. S1). Harmonic calculations of the fac and mer isomers of Re(CO)3(CH3CN)3+ (Fig. S2). Representative time-domain tag-loss signal for transient absorption experiments (Fig. S3). Nonresphasing pathways of a single oscillator system (Fig. S4). Pump pulse power dependence (Fig. S5). All rephasing and nonresphasing pathways for a two-oscillator system (Fig. S6). Transient action spectrum of protonated caffeine (Fig. S7).
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