Quantum control of optically driven molecular motor

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The main issues of this research project are to establish a theory of laser-induced molecular motors, and propose scenarios of their unidirectional motions. Our research works were concerned with two subjects : one was to propose a scheme of molecular motors driven in femtosecond time regime, and the other is to propose motors with rotational motions as quickly as possible. For the purpose of the first subject, a femotosecond pump-dump pulse excitation method was applied to a chiral molecular motor. That is, a rotational wave packet is created in an electronic excited state by a pumping pulse. The rotational wave packet is transferred to the ground state. We have shown by simulations that the unidirectional motion is determined by -analyzing time-resolved ionization spectra of motors. For the purpose of the other subject, a cis-trans isomerization of a molecule was considered as a model system. A unidirectional rotational motion with angular quantum number of 〜 100 in unit of Planck constant was created by an IR-UV sequential excitation. The quantum number is one-order high compared with that reported so far. It is also shown that unidirectional rotational motions of a chiral molecular motor are controlled by using laser pulses whose pulse shapes are designed by a quantum control method.