Abstract by Aldair Alejandro
Chemistry and Biochemistry
Using High-field Terahertz Spectroscopy to Measure Anharmonicity and Collisional Energy Transfer in Mono-fluorobenzene
Ultrafast spectroscopy is a powerful tool that uses ultrashort pulse lasers to study properties of materials on extremely small (picosecond) time scales. We use high-field terahertz (THz) spectroscopy to strongly excite vibrations in solids. Atoms inside the crystals can be moved far from their equilibrium positions using strong THz pulses, which can let us observe coupling between vibrations due to the anharmonic potential energy surface. Computational and experimental work on molecular systems reveals that anharmonic modes are most efficient in transferring energy when molecules collide. In this work, we want to use intense THz pulses to excite atoms in molecules far from their equilibrium positions in the gas phase instead of the solid phase, to also be able to predict which molecular vibrational modes are anharmonic, and therefore more important to energy transfer. Mono-fluorobenzene will serve as a useful starting point to measure its anharmonicity and how it impacts collisional energy transfer.