Real-time study of the femtosecond harpooning reaction in ${\mathrm{Ba}\mathrm{\cdots }\mathrm{FCH}}_3$

A real-time observation of an ultrafast intracluster harpooning reaction in an electronically excited metal atom-molecule complex is reported. Using the laser pump-probe technique the intracluster bimolecular reaction ${\mathrm{Ba}\mathrm{\cdots }\mathrm{FCH}}_3{\to \mathrm{B}\mathrm{a}\mathrm{F}+\mathrm{C}\mathrm{H}}_3$ has been investigated both in the real-time and frequency domains. The directly measured reaction time of 250 fs is in very good agreement with the decay time obtained by inverse Fourier transformation of the photodepletion spectrum of the parent ${\mathrm{Ba}\mathrm{\cdots }\mathrm{FCH}}_3$ cluster.