On molecular coherent rotational states

Norma Mankoč Borštnik

康裕 大島, Yasuhiro Ohshima

Jorge A. Morales, Erik Deumens, Yngve Öhrn

Coherent states suitable for the description of molecular rotations are developed and their connection to similar coherent states in the literature are explored. In particular their quasiclassical properties are developed. The use of such coherent states in time-dependent electron nuclear dynamics studies of molecular collision processes is discussed.

Luciano Fonda, N. Mankoč-Borštnik, Mitja Rosina

Shian Zhang, Wu Meizhen, Chenhui Lu +2 more

We theoretically demonstrate that the molecular rotational state populations through an impulsive nonresonant Raman process can be manipulated by shaping the femtosecond laser pulse with a periodic phase-step modulation. We show that, by precisely controlling these parameters characterizing the periodic phase-step modulation, both the odd and even rotational state populations can be completely suppressed or reconstructed as that induced by the transform-limited laser pulse, and the relative excitation between the odd and even rotational state populations can also be obtained. Furthermore, we show that the field-free molecular alignment can be manipulated due to the modulation of the odd and even rotational state populations.

Alec Owens, Andrey Yachmenev, Jochen Küpper

The control of ultrafast molecular rotational motion has benefited from the development of innovative techniques in strong-field laser physics. Here, we theoretically demonstrate a novel type of coherent control by inducing rotation of an asymmetric-top molecule about two different molecular axes. An optical centrifuge is applied to the hydrogen sulfide (H 2 S) molecule to create a molecular superrotor, an object performing ultrafast rotation about a well-defined axis. Using two distinct pulse envelopes for the optical centrifuge, we show that H 2 S can be excited along separate pathways of rotational states. This leads to stable rotation about two entirely different molecular axes while ensuring rotation is about the propagation direction of the centrifuge, i.e., the laboratory-fixed Z -axis. The presented scheme to control the angular momentum alignment of a molecule will, for instance, be useful in studies of molecule–molecule or molecule–surface scattering, especially due to the large amounts of energy associated with superrotors, which can even be controlled by changing the duration of the optical centrifuge pulse.