Characterization of the dynamics of unimolecular reaction of hydrazoic acid and hydrogen peroxide
Hutchinson, John S.
Master of Arts
Studies of intramolecular dynamics during unimolecular reactions are important in characterizing the energy transfer into the reaction coordinate responsible for the reactive event. We investigated the dynamics and mode-mode energy transfer immediately prior to the dissociation of hydrazoic acid and hydrogen peroxide. Hydrazoic acid decomposes into NH and N$\sb2$ when energy is "deposited" in the N-H stretch of the ground electronic state molecule by a pump laser. A specific vibrational motion generates an impulsive energy transfer, which leads to a singlet-triplet transition and subsequent central N-N bond fragmentation. Hydrogen peroxide decomposes into two OH fragments following overtone excitation of an O-H stretch via a specific bending motion capable of producing an impulse of energy flow into the reaction coordinate at the time of the O-O bond dissociation. Modeling the dynamics of overtone-excited HN$\sb3$, and using an existing model for the dynamics of overtone-excited H$\sb2$O$\sb2$, respectively, we first characterize the specificity of the vibrational dynamics preceding the reaction, then establish that these dynamics are stable, that is non-chaotic, and unique in the reaction.
Physical chemistry; Molecular physics