The absorption and fluorescence excitation spectrum of N2O in the 60-130 nm wavelength region

• Main Authors: He-Rong Yang, 楊和蓉
• Other Authors: J. B. Nee
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/58051952573386463658

碩士 === 國立中央大學 === 化學研究所 === 99 === abstract In this experiment, we have employed synchrotron radiation of NSRRC as the light source to study the absorption and fluorescence excitation of N2O in the 60-130 nm wavelength region. The beam line SEYA (4B1) with a resolution of 0.015-0.13 nm and the High Flux (3A1) with a resolution of 0.04-0.075nm have been used for measuring the absorption(ABS) and fluorescence excitation spectra (FES) experiments. Fluorescence signals were measured by using two photomultiplier tubes (EMI 9789QB, Hamamatsu R1460 for emissions produced by the excited states N2O+( 2Σ+, 2Π, 2Π+) and other neutral emissions. In the wavelength region 100-130 nm, our experimental results are compared with Shaw23. In 69-100 nm , our absorption spectrum are generally agreeable with the the spectra of Shaw et al23 (1992)with small difference in the absolute cross sections. In 60-96 nm, absorption spectrum are assigned to a few Rydeberg states convering to 2Π(2π-1, 12.886eV), 2Σ+(7σ-1,16.388eV), 2Π(1π-1,17.65 eV), 2Π+ (7σ-1,20.105eV). The FES experiments are discussed in three wavelength regions as follows: (1) In 74-80 nm, FES are produced by Rydberg states converging to N2O+ 2Σ+ which are comparable to previous works of Ukai et al.24(1992). In this wavelength region fluorescence produced in 175-320 nm are mainly contributed by Rydberg states ndπ and nsσ converging to N2O+( 2Σ) . Between 300-420 nm, there are vibrational levels (0,0,0) and (1,0,0) of the N2O+ 2Σ+ excited states. (2) In the wavelength region 69-75 nm, FES are mainly produced by vibrational levels of the excited states N2O+( 2Π) and weakly of N2O+( ). The intensity of N2O+( 2Π) decreases while shorter wavelength irradiation, but intensity of N2O+( ) is independent with wavelength. （3） In 60-69 nm, there are mainly ndπ and nsσ series converging to N2O+ 2Π+ with FES also contributed by N2O+( 2Σ+→ 2Π) showing window resonances observed for npπ series. Our results are compared with Lee et al.16 (1977) but with better resolution.