Laser Spectoscopy of Liquid Carbon, Q-Carbon, and Their Surfaces; Application to Material Science

We propose to advance our fundamental understanding of novel forms of carbon by performing detailed spectroscopy studies of their bulk and surfaces, using novel and state-of-the-art techniques.. Liquid and Q carbon will be prepared by non-thermal melting of both diamond and graphite targets. With femtosecond and nanosecond lasers. The vibrational and electronic structures of the bulk forms will be probed as a function of the delay time of the melting pulse (and thus as a function of temperature and pressure) with our recently developed chirped femtosecond coherent anti-Stokes Raman spectroscopy (c-CARS) technique. Our new broadband deep UV, electronic sum frequency generation (DUV-ESFG) spectroscopy technique will be used to probe the corresponding surfaces. Our Single Photon InfraRed Emission Spectroscopy (SPIRES) spectrometer will be used to monitor the evolution of the "super-undercooled" liquid carbon into the Q-carbon stages. Results from this collection of experiments will characterize the structure, bonding, and dynamics of liquid carbon, Q-carbon, and the various diamond structures(needles, nano/microdiamonds, ...) nucleated from Q-carbon. Time-resolved experiments will address the nucleation mechanisms of carbon nanotubes and diamond structures from the liquid and Q-carbon forms. Addition of dopants (e.g. N, B) to the diamond nano/micro-structures will be explored. The combined theoretical and experimental information obtained will ultimately be used to construct improved potential models that can describe properties of all known forms of carbon, and to predict additional, yet undiscovered forms that may be of much technical interest.