On the Prospects for Laser Cooling of TlF

TL;DR

This study measures vibrational branching ratios and the excited state lifetime of TlF, demonstrating highly suppressed off-diagonal decays, which supports the feasibility of laser cooling for fundamental physics experiments.

Contribution

The paper provides experimental measurements of vibrational branching ratios and excited state lifetime in TlF, confirming theoretical predictions and advancing prospects for laser cooling of TlF.

Findings

B state lifetime is 99(9) ns.

Off-diagonal vibrational decays are highly suppressed.

Experimental results agree with theoretical Franck-Condon calculations.

Abstract

We measure the upper state lifetime and two ratios of vibrational branching fractions f_{v'v} on the B^{3}\Pi_{1}(v') - X^{1}\Sigma^{+}(v) transition of TlF. We find the B state lifetime to be 99(9) ns. We also determine that the off-diagonal vibrational decays are highly suppressed: f_{01}/f_{00} < 2x10^{-4} and f_{02}/f_{00} = 1.10(6)%, in excellent agreement with their predicted values of f_{01}/f_{00} < 8x10^{-4} and f_{02}/f_{00} = 1.0(2)% based on Franck-Condon factors calculated using Morse and RKR potentials. The implications of these results for the possible laser cooling of TlF and fundamental symmetries experiments are discussed.