| Summary: | 碩士 === 國立成功大學 === 化學系碩博士班 === 95 === The transitions between the electronic states B1�優and X1�懲+ in gas phase of sodium dimer Na2 was observed by the laser-induced fluorescence spectroscopy (LIF). The Na2 molecule was pumped from the thermal populated X1�懲+ state to the excited B1�優 state by a 532 nm diode-pumped solid state laser. The LIF from B1�優 state to X1�懲+ state was collected and detected by a high-resolution double-grating monochromator system through a fiber module. The transitions can be described as:
Laser： B1�優(v’,J’) ← X1�懲+ (v1”,J1”) + h��1
Monochromator： B1�優 (v’,J’) →X1�懲+ (v2”,J2”) + h��2
The emission spectra from a mercury lamp and a magnesium hollow cathode lamp filled with argon were used as wavelength calibration. The line positions of atomic transitions of mercury, magnesium and argon were compared with the standard published on the website of National Institute of Standards and Technology.
The transition frequency of the fluorescence series corresponding to the laser excitation were compared with the initially calculation using the molecular constants from Kusch and Hessel in 1987 and recent work by Camacho et al. in 2005. We have observed 112 transitions from B1�優 state to X1�懲+ state belonging to four fluorescence series, (v’,J’)=(3,98),(4,63),(7,13), and (7,106) of B1�優 state back to the X1�懲+ state. The measured line positions and relative fluorescence intensities match well with the calculated from the molecular constants and Franck-Condon factors.
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