D. Zimdars et Kb. Eisenthal, Effect of solute orientation on solvation dynamics at the air/water interface, J PHYS CH A, 103(49), 1999, pp. 10567-10570
The ultrafast solvation dynamics of courmarin 314 (C314) molecules at the a
ir/water interface has been shown to depend on their orientation with respe
ct to the plane of the interface. A pump/second harmonic probe method using
femtosecond laser pulses were used to measure the interface solvation dyna
mics. The pump light was S polarized, i.e., in the interface plane, or P po
larized, i.e., in the plane perpendicular to the plane of the interface. Th
e S pumped C314 molecules yielded a solvation time of 820 +/- 60 fs, wherea
s P pumped yielded a solvation time of 1215 +/- 90 fs. The interface inhomo
geneous broadening on the solvation time scale is due to the differing orie
ntations of C314 at the air/water interface.