Multiple-Pulse, Single-Shot Femtosecond Spectroscopy of Condensed Phases

点击翻译按钮获取中文摘要

In this project in the Physical Chemistry Program of the Chemistry Division, Prof. Keith A. Nelson of the Massachusetts Institute of Technology will engage in a series of continuing investigations in the field of optical control of molecular and material behavior, including structural and chemical rearrangements in condensed media. These studies rely on the use of multiple-pulse femtosecond spectroscopy at visible, near-infrared or near-ultraviolet wavelengths. Shaped femtosecond pulse sequences are to be used to drive large-amplitude vibrations in crystal lattices to enable the spectroscopic observation of far-from-equilibrium crystal geometries. Additional work will concentrate on the development of an automated time-domain vibrational spectrometer, the manipulation of electronic coherences to observe coherent wavepacket dynamics in electronic levels accessible only through two-photon transitions, and other topics. The initial stages of the research will be devoted to the implementation of improved methods for the generation, characterization, and amplification of complex femtosecond waveforms. Current forefront research in physical chemistry includes the study of molecular processes at ultra-short time scales that correspond to the period of one molecular vibration ( a few femtoseconds). These investigations have the potential of providing methods for the control of molecular reactions and other dynamical processes, as well as providing optical analogs of the nuclear magnetic resonance technique to study condensed phase optical spectroscopy.