| Abstrakt: |
Fluorescence excitation spectra produced through photoexcitation of N2 using synchrotron radiation in the spectral region between 80 and 100 nm have been studied. Two broadband detectors were employed to simultaneously monitor fluorescence in the 115–320 nm and 300–700 nm regions, respectively. The peaks in the vacuum ultraviolet fluorescence excitation spectra are found to correspond to excitation of absorption transitions from the ground electronic state to the b 1Πu, b′ 1Σu+, cn 1Πu (with n=4–8), cn′ 1Σu+ (with n=5–9), and c4′(v′)1Σu+ (with v′=0–8) states of N2. The relative fluorescence production cross sections for the observed peaks are determined. No fluorescence has been produced through excitation of the most dominating absorption features of the b-X transition except for the (1,0), (5,0), (6,0), and (7,0) bands, in excellent agreement with recent lifetime measurements and theoretical calculations. Fluorescence peaks, which correlate with the long vibrational progressions of the c4′ 1Σu+ (with v′=0–8) and the b′ 1Σu+ (with v′ up to 19), have been observed. The present results provide important information for further unraveling of complicated and intriguing interactions among the excited electronic states of N2. Furthermore, solar photon excitation of N2 leading to the production of c4′(0) may provide useful data required for evaluating and analyzing dayglow models relevant to the interpretation of c4′(0) in the atmospheres of Earth, Jupiter, Saturn, Titan, and Triton. [ABSTRACT FROM AUTHOR] |
