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 analytical model potential function is proposed which captures the essential features of the transfer process, i.e. the H-atom motion and the heavy atom rearrangement. The parameters for this model potential are derived from high level abinitio quantum chemical calculations. The influence of those degrees of freedom which are not treated explicitly is modeled by means of their spectral density within density matrix theory. Various laser control strategies are studied putting emphasis on their robustness with respect to relaxation and dephasing processes. Laser pulse shapes are derived from the coherent dynamics by adjusting the parameters of analytically given fields and by using optimal control theory. It is found that compared to pump–dump control, laser driven hydrogen tunneling is more suited to achieve high yields in condensed phase situations. The applicability to other molecular systems showing intramolecular hydrogen transfer is discussed.