I was wondering if any one can help me calculate this integral using Mathematica. This is a form of integral representation of Hankel function of first kind:
(-1)^n/(I Pi[]) *
Integrate[ Exp[-k r (Sinh[t] Cos[tt]] + I Cosh[t] Sin[tt])] Exp[-n t],
{t,-Infinity, 0, PI[] I, Infinity + PI[] I}, PrincipalValue -> True])