The Van der Waals complex Li···FCH3 has been formed
in a crossed molecular beam apparatus.
The transition state (TS) for the reaction
Li*(2p 2P) + FCH3
LiF + CH3
was accessed at various configurations by laser-excitation
of the Li···FCH3 complex by tunable visible radiation,
1.
Photoinduced depletion of the complex by excitation to this TS was found
to occur across a broad range of
1
from 570 to 850 nm.
This action spectrum consisted of two broad regions located to either side
of the atomic transition line of
Li (2p 2P
2s 2S).
The first region, between 700 and 850 nm, was dominated by sharp maxima
in the depletion intensity.
A broad peak with weakly-resolved structure characterized the second region,
between 570 and 680 nm.
These findings were interpreted by means of high-level ab initio
calculations of the potential-energy surfaces in the TS region.
The peaks in the photodepletion spectrum were assigned to specific electronic
transitions, their shapes and intensities being explained in terms of
calculated transition-dipole moments and rovibrational wavefunctions.