Control of diabatic versus adiabatic field dissociation in a heavy Rydberg system.

A novel phenomenon is observed in the dynamics of laser-prepared coherent wave packets, bound by the Coulombic 1/r potential of an ion-pair system. After exciting weakly bound (approximately 3 meV) H(+)(-) wave packets in a Stark field, and permitting them to evolve in time, control of field dissociation via adiabatic and diabatic routes is demonstrated by applying delayed pulsed-electric fields, involving a zero-field crossing. Control manifests itself through the production of ions from each pathway at a different instant in time. This phenomenon is applied to map the oscillatory behavior of an angular momentum wave packet in a heavy Rydberg system. The characteristic frequencies of the observed Stark oscillations verify predicted mass-scaling laws for heavy Rydberg systems.

Complications of scalp reductions.

Early problems with central sagittal scalp reductions are primarily medical and surgical. As they resolve with surgical experience, the cosmetic problems become more apparent. These problems and complications are outlined along with suggestions for prevention and correction.