THE LINE-PROFILES OF SINGLE ROTATIONAL LINES OF THE H-2 B-X(3,0) BANDIN AN INTENSE INFRARED LIGHT-FIELD

The first investigation of the lineshape of single rotational lines of the H-2 B - X(3, 0) band in an intense infrared light field (lambda = 1064 nm) at intensities between 10(10) W/cm(2) and 10(12) W/cm(2) is reported. The B - X(3, 0) band is excited with low intensity vacuum ul traviolet radiation (lambda approximate to 106 nm). B-state excitation is observed by multiphoton ionization and dissociation of H-2 with H as final product. The lineshapes of the B - X(3, 0) band behave diffe rently in both decay channels. This indicates that they branch before the molecule is photoionized. The intensity dependence of the lineshap es seems to show that at certain intensities in the focused infrared l ight beam the AC-Stark effect induces transient resonances into the mu ltiphoton excitation process starting at the B(upsilon = 3, J) rotatio nal levels, A qualitative analysis of the states which may influence t he B(upsilon = 3, J) multiphoton excitation rate is given.