Abstract
CO molecules in a supersonic molecular beam are resonantly excited from the X 1Σ+, ν′'=0 ground state to the a 3Π, ν′=0 metastable state using pulsed laser radiation at 206 nm. In the excitation region a static electric field is applied to split individual M components of a given rotational line of this electronic transition. The splitting can be made larger than the Fourier-limited bandwidth of the pulsed radiation source and specific M levels in the a 3Π state can be populated. Peak fluxes of 1017 (1015) oriented CO a 3Π1, ν′=0, J′=1, M′=1 (a 3Π2, ν′=0, J′=2, M′=2) molecules per second are obtained.