Pulse train induced rotational excitation and orientation of a polar molecule

•Rotational excitation and orientation of a polar molecule is studied in presence of pulse train of different shape envelopes.•Both rotational excitation and orientation show strong dependence on shape of the pulse train.•Rotational dynamics and orientation show strong dependence on the shape of the pulse train.

We investigate theoretically the rotational excitation and field free molecular orientation of polar HBr molecule, interacting with train of ultrashort laser pulses. By adjusting the number of pulses, pulse period and the intensity of the pulse, one can suppress a population while simultaneously enhancing the desired population in particular rotational state. We have used train of laser pulses of different shaped pulse envelopes. The dynamics and orientation of molecules in the presence of pulse train of different shapes is studied and explained.

Graphical AbstractThe figure shows the effect of thirteen pulse train (Gaussian shape) on the population dynamics of ground and excited rotational states of HBr molecule. Inset shows the orientation of the molecule due to single pulse.Figure optionsDownload full-size imageDownload as PowerPoint slide