INVESTIGATION OF PHOTON-EMISSION SPECTRA OF HYDROGEN USING INTENSE SUBPICOSECOND TI-SAPPHIRE ND-GLASS LASER-PULSES

High-harmonic generation processes have been experimentally investigat ed in molecular hydrogen gas as both molecular dissociation and ioniza tion occur in the gas. The high harmonics observed in our experiment c an be mainly attributed to neutral hydrogen molecules. Besides the har monic spectra, two strong Lyman lines from the dissociated hydrogen at oms and the emission from the neutral hydrogen molecules are observed. Several possible excitation and dissociation channels of hydrogen mol ecules are proposed. It is found that resonance effects are important for both high-harmonic generation and molecular dissociation. Theoreti cal calculations using the time-dependent Hartree-Fock (TDHF) method f or H-2 reproduce some of the resonance effects.