Laser optogalvanic and jet spectroscopy of germylene (GeH2):: New spectroscopic data for an important semiconductor growth intermediate

The (A) over tilde B-1(1)-(X) over tilde (1)A(1) electronic transition of germylene has been reinvestigated. A room temperature absorption spectrum of the: central portion of the 0(0)(0) band of GeH2 has been obtained using the technique of laser optogalvanic spectroscopy. A rotationally resolved spectrum of the 0(0)(0) band of jet-cooled GeD2 has been recorded with a pulsed discharge source. Analysis of these spectra has yielded ground and excited state rotational constants for the (GeH2)-Ge-74, (GeH2)-Ge-72, (GeH2)-Ge-70, (GeD2)-Ge-76, (GeD2)-Ge-74, (GeD2)-Ge-72, and (GeD2)-Ge-70 isotopomers and approximate equilibrium structures of: r"(Ge-H) =1.5883(9) Angstrom, theta"(H-Ge-H)=91.22(4)degrees. r'(Ge-H)=1.5471(6) Angstrom, and theta'(H-Ge-H) =12.3.44(2)degrees. The ground state v(1) and v(2) vibrational frequencies have been determined from wavelength-resolved fluorescence spectra of jet-cooled GeH2 and GeD2. There is good evidence that GeH2 rotational levels with K'(a)>1 are so strongly predissociated that lifetime broadening makes them diffuse, severely restricting the information that can be obtained from absorption and laser-induced fluorescence experiments. (C) 2000 American Institute of Physics. [S0021-9606(00)00645-0].