than, the Integral p&th becomes that shown In Figure 5. The integral path, Lj, 

 ie now transferred onto the path C, In Figure 5 as 



e c 



v(c - iw) r e" 



— du • e ° J — — dv 



(39) 



(Li) 



The Integral over C, can be easily evaluated tflth the nethod of residue as 



-v 



c l 



-2*li w < o 



dv + { }, „ 



u > o 



u a (s - lu>) 



with the introduction of the exponential integral 



(40) 



I £ dv - E,[~u (2 - iu)], 



I v * 



-« (z - 13) 



(41) 



the Integral over C, becomes 



-2*i» w < o 



/.a-.V:-.B l [^ (T-i3>]*-.r ( * 1 ».2J 



r v * to > o 



(42) 



12 



