Nadeem, Ali (2001) Laser Spectroscopic Studies of Bound and Autoionizing Spectra of Tin. PhD thesis, Quaid-i-Azam University, Islamabad.
The present work have been carried out to study the even parity bound and autoionizing spectra of tin using the two-step laser excitation technique in conjunction with an atomic beam apparatus. We have used two intermediate levels 5p6s(l/2,1/2)( and 5p6s(3/2,1/2)1 to record the spectra of tin. In the first experiment the 5p6s(l/2,1/2)( intermediate level at 34914.20 Â± 0.02 cm-1 was populated using the second harmonic of the first dye laser and the second laser was scanned up to the first ionization threshold. The 5pnp (1/2,3/2)2 (II â‰¤ n â‰¤ 45) and 5pnp (1/2,3/2)1 (12 â‰¤ n â‰¤ 18) Rydberg series have been observed for the first time. In addition, five p-levels 5p8p (3/2,1/2)1,2, 5p8p (3/2,3/2)0,1,2 and three f-levels 5p5f (3/2,5,2)1,2 and 5p5f (3/2,7/2)2 attached to the second ionization threshold have been detected. The inter-channel interactions among the J = 2 levels were studied using the three channel model of the phase shifted quantum defect theory. In the subsequent experiments, the 5p6s(3/2,1/2)1 intermediate level at 39257.1Â± 0.02 cm-1 was selected as a first step excitation. As a result, new data on the 5pnf (1/2,5/2)2 (12 â‰¤ n â‰¤ 46), 5pnp (1/2,1/2)1 (20 â‰¤ n â‰¤ 31) and 5pnP (1 /2,3/2)2 (16 â‰¤ n â‰¤ 56) Rydberg series have been acquired. The interactions among the 5pnf (1/2,5/2)2 and the 5pnf (3/2,5/2)2 series has been studied using a two channels quantum defect theory. In addition the even parity autoionizing resonances between the 5p2PI/2 and 5p2P3/2 ionic limits tin, excited from the 5p6s 1P1 (3/2,1/2)1 intermediate level have been detected. The Rydberg series are assigned as 5pnf(3/2,7/2)2 (6 â‰¤ n â‰¤ 34), 5pnf(3/2,5/2)2 (6 â‰¤ n â‰¤ 18), 5pnf (3/2,5/2)1 (6 â‰¤ n â‰¤ 11), 5pnp (3/2,1/2)2 (9 â‰¤ n â‰¤ 37), 5pnp (3/2.1/2)1 (9 â‰¤ n â‰¤ 18), 5pnp (3/2,3/2)2 (9 â‰¤ n â‰¤ 27) and 5pnp (3/2,3/2)1 (9 â‰¤ n â‰¤ 18). The observed spectra in the autoionizing region are simulated within the framework of the multi-channel quantum defect theory. In all, we report about 200 new even-parity bound and autoionizing levels in the spectra of neutral tin for the first time.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||laser spectroscopic studies, autoionizing spectra, tin, yag laser, dye-laser, two step laser excitation|
|Subjects:||Physical Sciences (f) > Physics(f1)|
|Deposited By:||Mr. Javed Memon|
|Deposited On:||20 Jul 2009 13:32|
|Last Modified:||10 Oct 2009 17:47|
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