https://doi.org/10.1140/epjd/e2007-00278-2
Influence of pressure on the relative population of the two lowest vibrational levels of the C 3Πu state of nitrogen for electron beam excitation
1
Physik Department E12, Technische Universität München, 85748 Garching, Germany
2
Coherent GmbH, Zielstattstrasse 32, 81379 München, Germany
Corresponding author: a andrei.morozov@ph.tum.de
Received:
14
June
2007
Revised:
4
September
2007
Published online:
28
September
2007
Continuous and pulsed 12 keV electron beams were used to excite nitrogen within a gas cell at pressures ranging from 10 to 1400 hPa. The pressure dependence of the ratio of photon fluxes for emission from vibrational levels v'=0 and 1 of the C 3Πu state has been studied. The results confirm the presence of a collisional excitation mechanism populating v'=0, 1 in addition to electron impact excitation. Rate constants of (1.27 ±0.04)×10-11 cm3s-1 [ v'=0] and (2.68 ±0.08)×10-11 cm3s-1 [ v'=1] were measured for C 3Πu quenching by ground state nitrogen. For electron beam conditions relative excitation efficiencies of 1:0.59:0.22 for vibrational levels 0, 1 and 2 were calculated. The recorded flux ratios are compared with the predictions given by a vibrational relaxation model.
PACS: 34.80.Gs – Molecular excitation and ionization by electron impact / 33.70.Fd – Absolute and relative line and band intensities / 33.50.Hv – Radiationless transitions, quenching
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007