Coherent Control of Y\ô ê oOARydberg Wave Packets

New experiments and theory contributing to the understanding of the dynamics and control of molecular Rydberg wave packets are presented. An intuitive scheme for controlling the rotational quantum state of a Rydberg molecule is demonstrated experimentally. We determine the accumulated phase difference between the various components of a molecular electron wave packet, and then employ a sequence of phase-locked optical pulses to selectively enhance or depopulate specific rotational states. The angular momentum composition of the resulting wave packet, and the efficiency of the control scheme, is determined by calculating the multipulse response of the time dependent Rydberg populations. The dynamics of predissociating Rydberg electron wavepackets are observed using the optical Ramsey method. The time-resolved spectra are hydrogenic and are very well modeled by assuming that only one p Rydberg series contributes to the dynamics. This is in contrast with previous observations of autoionising Rydberg electron wave packets which show quite dramatic deviations from hydrogenic behaviour above the Bom-Oppenheimer limit. The origin of these deviations lies in the interplay between electronic and molecular phase. By exploiting these phases we are able to control the ratio of predissociaton to autoionisation A multichannel quantum defect theory analysis of the Rydberg state of NO is undertaken. The analysis takes into account all the accessible series with / < 3 and all documented interseries interactions. This analysis is the most complete description of NO to date and will aid in the design of future coherent control experiments. This thesis is based on the following publications Chapter 3 Optical control o f the rotational angular momentum o f a molecular Rydberg wave packet. R.S. Minns, R. Patel, J.R.R. Verlet and H.H. Fielding. Phys. Rev. Lett. 91, 243601 (2003) Chapter 4 Observation and control o f autoionising and predissociating Rydberg electron wave packets in NO. R.S. Minns, J.R.R. Verlet, L.J. Watkins and H.H. Fielding. J. Chem. Phys. 119 (12), 5842 (2003) Chapter 5 Global MQDT representation o f the NO molecule. R.S. Minns, J.W. Hepburn, H.H. Fielding and Ch. Jungen. J. Mol. Spec. In preparation Additional publications Controlling the angular momentum composition o f a Rydberg electron wave packet. J.R.R. Verlet, V.G. Stavros, R.S. Minns and H.H. Fielding. Phys. Rev. Lett. 89 (26), 263004 (2002). Controlling the radial dynamics o f Rydberg wave packets in Xe using phase-locked optical pulses. J.R.R. Verlet, V.G. Stavros, R.S. Minns and H.H. Fielding. J. Phys. B-At. Mol. Opt. Phys. 36 (17), 3683 (2003). Interfering Rydberg wave packets in Na. R.E. Carley, E.D. Boleat, R.S. Minns, R. Patel and H.H. Fielding J. Phys. B-At. Mol. Opt. Phys. In preparation