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Unformatted text preview: p → q , and is given by: A pq = 8 π 2 e 2 ν 3  r pq  2 3¯ h ε c 3 with r pq = ± ψ p  ± r  ψ q ² For hydrogenic atoms holds: A p = 1 . 58 · 10 8 Z 4 p4 . 5 , with A p = 1 / τ p = ∑ q A pq . The intensity I of a line is given by I pq = hfA pq n p / 4 π . The Einstein coef±cients B are given by: B pq = c 3 A pq 8 π h ν 3 and B pq B qp = g q g p A spectral line is broadened by several mechanisms: 1. Because the states have a ±nite life time. The natural life time of a state p is given by τ p = 1 / ∑ q A pq . From the uncertainty relation then follows: Δ ( h ν ) · τ p = 1 2 ¯ h , this gives Δ ν = 1 4 πτ p = ∑ q A pq 4 π The natural line width is usually ³ than the broadening due to the following two mechanisms:...
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This note was uploaded on 01/30/2011 for the course PHYSICS 208 taught by Professor Ye during the Spring '10 term at Blinn College.
 Spring '10
 Ye
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