Acta Phys. -Chim. Sin. ›› 1997, Vol. 13 ›› Issue (07): 617-620.doi: 10.3866/PKU.WHXB19970708

• ARTICLE • Previous Articles     Next Articles

Abnormal Pressure Effects of H2 Three-photon Resonant Enhanced Ionization Spectroscopy

Zhang Gui-Qiu,Sha Guo-He,Xu Ji-Jun,Knott W.Proch D   

  1. Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023|Max-Planck-Institut fur Quantenoptik,P.O.Box 1513,D-85740 Garching,Germany
  • Received:1996-11-19 Revised:1997-02-25 Published:1997-07-15
  • Contact: Sha Guo-He


The three-photon resonant ionization spectroscopy of H2 B1∑u+-X1∑g+ (12,0) and C1Ⅱu-X1∑g+ (2,0) exhibits abnormal pressure effects. Some of them are observed for the first time. Pressure-induced abnormal line shift, line broadening, line splitting and spectral intensity variations can be well explained by a mechanism of reabsorption of the third harmonic generation in the medium. Approximate expressions considering the phase matching requirement yield lineshifts, -splitting and -intensities at different pressures in good agreement with the experimental results. Two similar spectra are detected by two tandem electrode pairs in a gas celll which give experimental evidence for THG reabsorption mechanism. The failure to obtain ion signal from circularly polarized light also supports the above mechanism.

Key words: Molecular hydrogen, Abnormal pressure effects, 3-Photon REMPI, Third harmonic generation