  The lifetimes of the lower-lying vibrational states of ultralong-range
strontium Rydberg molecules comprising one ground-state 5s2 1S0 atom and one
Rydberg atom in the 5s38s 3S1 state are reported. The molecules are created in
an ultracold gas held in an optical dipole trap and their numbers determined
using field ionization, the product electrons being detected by a microchannel
plate. The measurements show that, in marked contrast to earlier measurements
involving rubidium Rydberg molecules, the lifetimes of the low-lying molecular
vibrational states are very similar to those of the parent Rydberg atoms. This
results because the strong p-wave resonance in low-energy electronrubidium
scattering, which plays an important role in determining the molecular
lifetimes, is not present for strontium. The absence of this resonance offers
advantages for experiments involving strontium Rydberg atoms as impurities in
quantum gases and for testing theories of molecular formation and decay.
