Mixed-field orientation of a thermal ensemble of linear polar molecules

We present a theoretical study of the impact of an electrostatic field combined with nonresonant linearly polarized laser pulses on the rotational dynamics of a thermal ensemble of linear molecules. We solve the time-dependent Schr\"odinger equation within the rigid rotor approximation for several rotational states. Using the carbonyl sulfide (OCS) molecule as a prototype, the mixed-field orientation of a thermal sample is analyzed in detail for experimentally accessible static field strengths and laser pulses. We demonstrate that for the characteristic field configuration used in current mixed-field orientation experiments, a significant orientation is obtained for rotational temperatures below 0.7K or using stronger dc fields.Comment: 9 pages, 10 figure

Fine Structure of Open Shell Diatomic Molecules in Combined Electric and Magnetic Fields

We present a theoretical study of the impact of an electric field combined with a magnetic field on the rotational dynamics of open shell diatomic molecules. Within the rigid rotor approximation, we solve the time-independent Schr\"odinger equation including the fine-structure interactions and the \Lambda-doubling effects. We consider three sets of molecule specific parameters and several field regimes and investigate the interplay between the different interactions identifying the dominant one. The possibility of inducing couplings between the spin and rotational degrees of freedom is demonstrated.Comment: 11 pages, 16 figure

Non-adiabatic effects in long-pulse mixed-field orientation of a linear polar molecule

We present a theoretical study of the impact of an electrostatic field combined with non-resonant linearly polarized laser pulses on the rotational dynamics of linear molecules. Within the rigid rotor approximation, we solve the time-dependent Schr\"odinger equation for several field configurations. Using the OCS molecule as prototype, the field-dressed dynamics is analyzed in detail for experimentally accessible static field strengths and laser pulses. Results for directional cosines are presented and compared to the predictions of the adiabatic theory. We demonstrate that for prototypical field configuration used in current mixed-field orientation experiments, the molecular field dynamics is, in general, non-adiabatic, being mandatory a time-dependent description of these systems. We investigate several field regimes identifying the sources of non-adiabatic effects, and provide the field parameters under which the adiabatic dynamics would be achieved.Comment: 16 pages, 16 figures. Submitted to Physical Review

Full Control of non-symmetric molecules orientation using weak and moderate electric fields

We investigate the full control over the orientation of a non-symmetric molecule by using moderate and weak electric fields. Quantum Optimal Control techniques allow us to orient any axis of 6-chloropyridazine-3-carbonitrile, which is taken as prototype example here, along the electric field direction. We perform a detailed analysis by exploring the impact on the molecular orientation of the time scale and strength of the control field. The underlying physical phenomena allowing for the control of the orientation are interpreted in terms of the frequencies contributing to the field-dressed dynamics and to the driving field by a spectral analysis.Comment: 8 pages and 6 figure