Molecular alignment echoes probing collision-induced rotational-speed changes

Probing nonadiabatic molecular alignment by spectral modulation.

We investigated molecular alignment wakes of femtosecond laser pulses. Evolution of nonadiabatic molecular alignment in nitrogen gas has been measured via its nonlinear interaction effects with a variably delayed probe pulse. The induced rotational wave packet was mapped as a function of the angular difference between polarization directions of femtosecond pump and probe pulses as well as their...

Rotational excitation and molecular alignment in intense laser fields

Rotational excitation and spatial alignment in moderate intensity radiation fields are studied numerically and analytically, using time-dependent quantum mechanics. Substantial rotational excitation is found under conditions typically used in time-resolved spectroscopy experiments. The broad rotational wave packet excited by the laser pulse is well defined in the conjugate angle space, peaking ...

Probing ultrafast thermalization with field-free molecular alignment

Collision-induced conformational changes in glycine.

We present quantum dynamical calculations on the conformational changes of glycine in collisions with the He, Ne, and Ar rare-gas atoms. For two conformer interconversion processes (III-->I and IV-->I), we find that the probability of interconversion is dependent on several factors, including the energy of the collision, the angle at which the colliding atom approaches the glycine molecule, and...

Electron-Collision-Induced Alignment of Rare Gases near Threshold

Results of a semirelativistic R-matrix calculation are compared with experimental values for light polarizations and alignment parameters of the second excited-state manifolds of neon and krypton following electron impact excitation. The calculations focus on the near-threshold regime, where negative-ion resonances have a significant effect on the atomic alignment. A grouping of the alignment v...