The polarisation of the hydroxyl fragment radiation arising from highly rotational excited OH radicals produced in the electron-impact dissociation of H2O has been measured for incident energies ranging from just above threshold (9.3 eV) up to 500 eV. Whereas the OH fluorescence is essentially unpolarised for energies greater than about 150 eV, a significantly non-zero polarisation occurs when the impact energy approaches threshold; by monitoring either pure P-branch fluorescence or a mixture of P- and predominantly Q-branch radiation extrapolated threshold polarisations of +7 and -9%, respectively, are obtained. The sign of the polarisation at threshold implies that rapidly rotating (abnormal) hydroxyl radicals arise from a parent H2O state of symmetry A1.
|Original language||English (US)|
|Journal||Journal of Physics B: Atomic and Molecular Physics|
|State||Published - 1981|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics