Ultrafast photoinduced dissipative hydrogen switching dynamics in thioacetylacetone

Different schemes for controlling the isomerization of thioacetylacetone by means of shaped laser pulses are investigated here. A two-dimensional anal ytical model potential function is proposed which captures the essential fe atures of the transfer process, i.e. the H-atom motion and the heavy atom r earrangement. The parameters for this model potential are derived from high level ab initio quantum chemical calculations. The influence of those degr ees of freedom which are not treated explicitly is modeled by means of thei r spectral density within density matrix theory. Various laser control stra tegies are studied putting emphasis on their robustness with respect to rel axation and dephasing processes. Laser pulse shapes are derived from the co herent dynamics by adjusting the parameters of analytically given fields an d by using optimal control theory. It is found that compared to pump-dump c ontrol, laser driven hydrogen tunneling is more suited to achieve high yiel ds in condensed phase situations. The applicability to other molecular syst ems showing intramolecular hydrogen transfer is discussed.