Selective detection of O(1S0) following electron impact dissociation of O2 and N2O using a XeO* conversion technique

Optical and electron spin resonance studies of xenon-nitrogen-helium condensates containing nitrogen and oxygen atoms

We present the first observations of excimer XeO* molecules in molecular nitrogen films surrounding xenon cores of nanoclusters. Multishell nanoclusters form upon the fast cooling of a helium jet containing small admixtures of nitrogen and xenon by cold helium vapor (T = 1.5 K). Such nanoclusters injected into superfluid helium aggregate into porous impurity-helium condensates. Passage of helium gas with admixtures through a radio frequency discharge allows the storage of high densities of radicals stabilized in impurity-helium condensates. Intense recombination of the radicals occurs during destruction of such condensates and generates excited species observable because of optical emission. Rich spectra of xenon-oxygen complexes have been detected upon destruction of xenon-nitrogen-helium condensates. A xenon environment quenches metastable N((2)D) atoms but has a much weaker effect on the luminescence of N((2)P) atoms. Electron spin resonance spectra of N((4)S) atoms trapped in xenon-nitrogen-helium condensates have been studied. High local concentrations of nitrogen atoms (up to 10(21) cm(-3)) stabilized in xenon-nitrogen nanoclusters have been revealed.

S(1S) production following electron impact on thiophosgene (Cl2CS)

A special xenon matrix detector has been used to study the production of S(1S) following controlled electron impact on thiophosgene (Cl2CS) targets over an electron energy range from threshold to 400 eV. Time-of-flight spectroscopy has been used to measure S(1S) fragment kinetic energies. Fragments with energies in excess of 1 eV have been observed. The absolute cross section for S(1S) production reaches a maximum of [1.05+/-0.35] x 10(-18) cm2 at approximately 125 eV impact energy. Two different fragmentation processes, involving triplet and singlet excited states of the parent Cl2CS molecule, have been identified.

Oxygen reactions in high-pressure nitrogen gas studied with optical emission spectroscopy

A study of some oxygen reactions in irradiated high-pressure (0.34-3.3MPa) nitrogen gas is presented. Nitrogen gas containing < or =1ppm H(2)O and O(2) was irradiated in a closed target chamber with 4.3MeV protons. Optical emission spectra of the NO-gamma (A(2)Sigma(+)-X(2)Pi), the NO-beta (B(2)Pi-X(2)Pi) and the O ((1)S-(1)D) transitions were recorded as a function of irradiation time at four different nitrogen-gas pressures. The results show a coupling between the NO-gamma build-up half time and the NO-beta decay and the O ((1)S-(1)D) decay half times as a function of irradiation time. The binding of free atomic oxygen in reactions forming NO has implications for the balance of [(11)C]CO(2) versus [(11)C]CO production.