The VUV Absorption Spectrum of Lead Monoxide.

The VUV absorption spectrum of PbO vapor down to 300 Å has been observed for the first time. Four ionization energies have been determined from Rydberg series at 8.73, 8.83, 12.81, and 26.28 eV corresponding to the X(2)Pi, A(2)Sigma(+), B(2)X(+), and C(2)Sigma(+) electronic states of the PbO(+) ion. Copyright 2000 Academic Press.

Rydberg States of SiCl.

A fluorescence spectrum, excited by the synchrotron radiation of Superaco in a microwave discharge through He + SiCl(4), leads to the observation of five new electronic states of SiCl, converging to the ground X(1)Sigma(+) state of the SiCl(+) ion. The (n s varsigma) and (n p pi) Rydberg series are extended respectively to n = 6 and n = 7. A new ionization limit is observed in absorption at 11.238 eV corresponding to the a(3)Pi electronic state of SiCl(+). Four new states are observed which converge to that limit. Copyright 1999 Academic Press.

The VUV Absorption Spectrum of the GeO Molecule.

The absorption spectrum of GeO, between 2000 and 300 Å, was recorded using the facilities of the SUPERACO synchrotron radiation in Orsay, France. The first three ionization limits, corresponding to the X(2)Sigma(+), A(2)Pi, and B(2)Sigma(+) states of the GeO(+) ion, were confirmed at 11.2814, 11.42, and 15.048 eV, respectively. The fourth ionization limit corresponding to the C(2)Sigma(+) ionic state was measured for the first time at 31.47 eV, in reasonable agreement with theoretical calculations. Copyright 1999 Academic Press.

The VUV Absorption Spectra of SiF and SiF+

The absorption spectrum of a microwave discharge (2450 MHz) in flowing helium with traces of SiF4 has been recorded on the SA61 beam line of SUPERACO between 2000 and 500 Å. Two new ionization energies have been observed at 15.12 and 17.27 eV corresponding, respectively, to the A1Pi and B1Sigma+ states of SiF+. The A1Pi <-- X1Sigma+ transition of the ion has been identified for the first time on high-resolution spectra obtained in 1992 with the 35-foot Eagle spectrograph in Meudon. Copyright 1999 Academic Press.

The VUV Absorption Spectrum of the Tin Monoxide Molecule

The absorption spectrum of heated SnO between 2000 and 300 A has been recorded using the facilities of the SuperACO synchrotron at Orsay, France. New bands have been observed which supplement the data on the previously known systems of SnO. Newly discovered Rydberg series have confirmed the four ionization potentials observed or calculated by Dyke et al. (1982. Chem. Phys. 67, 245). Copyright 1998 Academic Press. Copyright 1998Academic Press