Zhongying Yan and KyungIn Kim

Advisor: Elizabeth McCormack

Department of Physics


Probing the Energies of the Highest Vibrational Levels of the 4 1 State of the H2 molecule


The vibrational and rotational structures and perturbations of the 4 1 state of H2 have been investigated by using resonantly enhanced multi-photon ionization (REMPI) spectroscopy. This state is located well above the ionization energy and several dissociation energies of the molecule and is not yet well understood.

Spectra are obtained through laser absorption via rotational levels of the E, F 1,  = 6 state and are recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. Term energies and rotational constants for the v = 8 - 13, J = 0 - 3 levels of the 4 1  state are measured and compared to theoretical predictions made by integrating the Schrdinger equation for this state. Interactions between levels of the 4 1 and  1state vibrational levels are studied by analyzing the perturbations observed in the spectra.

These measurements contribute to a comprehensive understanding of the highly mixed states found in this energy region where dissociation and ionization compete as decay mechanisms.