Permanent electric dipole moments of metal containing molecules

A summary of the current status of experimentally derived values of the permanent electric dipole moment, μ, for the 3s, 4s, 5s, and 6s series of transient metal containing molecules is given. The experimental methods employed are described with particular emphasis placed upon optical Stark measurements of supersonic molecular beam samples. The complications associated with the analysis of optical Stark spectra of open shell polyatomic metal containing radicals are addressed. An assessment of the applicability of simple molecular orbital correlation diagrams to predict trends in measured values of μ for early transition metal diatomic molecules is made.