Photodissociation and spectroscopy of alkali metal dimers in supersonic molecular beam

Alkali metal dimers provide a good system to study the perturbation and photodissociation dynamics of the excited states since they have many electronic states that absorb light from the near-IR to UV region. Some of the electronic states predissociate to produce excited atoms. Theoretical treatments of alkali metal dimers are much simpler than those are for other diatomic molecules because alkali metal dimers have two valence electrons. The resonance enhanced two-photon ionization (RE2PI) spectra of various alkali metal dimers such as Rb/sub 2/, RbCs, KRb, K/sub 2/ are observed in supersonic molecular beam. We use high temperature pulsed nozzle to generate a very cold molecular beam of alkali metal dimers. Alkali metal dimers are prepared with vibrational temperature of less than 5 K and rotational temperature of 1 K. By combining the time-of-flight mass spectrometric detection with supersonic molecular beam the excitation spectra become very simplified and show highly enhanced detection sensitivity.