Laser-driven torsional coherences

We discuss several interesting phenomena in the dynamics of strong field-triggered torsional wavepackets, which carry implications for the problem of torsional alignment in nonrigid molecules. Our results point to the origin and consequences of the fundamental differences between rotational and torsional coherences. In addition, we provide design guidelines for torsional control experiments by illustrating the role played by the laser intensity, pulse width, temperature, and molecular parameters. Specifically, as an example of several classes of molecules expected to make suitable candidates for laboratory experiments, we explore the torsional control of 9-[2-(anthracen-9-yl)ethynyl]anthracene and contrast it with that of biphenyl. Finally, we propose several potential applications for coherent torsional control in chemistry, physics, and material science. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773009]