Control by decoherence: weak field control of an excited state objective
- Hebrew University of Jerusalem, (Israel)
- Northwestern Univ., Evanston, IL (United States)
Coherent control employing a broadband excitation is applied to a branching reaction in the excited state. In a weak field for an isolated molecule, a control objective is only frequency dependent. This means that phase control of the pulse cannot improve the objective beyond the best frequency selection. Once the molecule is put into a dissipative environment a new timescale emerges. In this study, we demonstrate that the dissipation allows us to achieve coherent control of branching ratios in the excited state. The model studied contains a nuclear coordinate and three electronic states: the ground and two coupled diabatic excited states. The influence of the environment is modeled by the stochastic surrogate Hamiltonian. The excitation is generated by a Gaussian pulse where the phase control introduced a chirp to the pulse. For sufficient relaxation, we find significant control in the weak field depending on the chirp rate. The observed control is rationalized by a timing argument caused by a focused wavepacket. The initial non-adiabatic crossing is enhanced by the chirp. This is followed by energy relaxation which stabilizes the state by having an energy lower than the crossing point.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Bio-Inspired Energy Science (CBES)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Contributing Organization:
- Fritz Haber Research Center for Molecular Dynamics, (Israel)
- DOE Contract Number:
- SC0000989
- OSTI ID:
- 1065498
- Journal Information:
- New Journal of Physics, Vol. 12, Issue 1; Related Information: CBES partners with Northwestern University (lead); Harvard University; New York University; Pennsylvania State University; University of Michigan; University of Pittsburgh
- Country of Publication:
- United States
- Language:
- English
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