High-resolution spectroscopy of triplet states of Rb2 by femtosecond pump-probe photoionization of doped helium nanodroplets

TL;DR

This study investigates vibrational wave packet dynamics in triplet states of Rb2 molecules on helium nanodroplets using femtosecond pump-probe photoionization, revealing detailed vibrational spectra and wave packet revivals.

Contribution

It provides high-resolution vibrational spectra of Rb2 triplet states and demonstrates the use of femtosecond pump-probe spectroscopy for long-time wave packet dynamics.

Findings

Observation of full and fractional revivals in the (1)^3Σ_g^+ state

High-resolution vibrational spectra matching ab initio calculations

Long-lived wave packet oscillations exceeding 1.5 ns

Abstract

The dynamics of vibrational wave packets in triplet states of rubidium dimers (Rb2) formed on helium nanodroplets are studied using femtosecond pump-probe photoionization spectroscopy. Due to fast desorption of the excited Rb2 molecules off the droplets and due to their low internal temperature, wave packet oscillations can be followed up to very long pump-probe delay times >1.5ns. In the first excited triplet state (1)^3\Sigma_g^+, full and fractional revivals are observed with high contrast. Fourier analysis provides high-resolution vibrational spectra which are in excellent agreement with ab initio calculations.