Exact initial transverse susceptibility for a random-bond Ising chain

The exact initial transverse susceptibility, chi(perpendicular to), of a random-bond Ising chain has been derived by a method based on the use of a statistical identity of the type introduced by Callen and by Suzuki for spin correlation functions. Besides being applicable to general random-bond Ising chains, among which the uniform and alternating-bond Ising chains are special examples, the method is particularly simple in comparison to the exact derivation of chi(perpendicular to) for the uniform Ising chain that already exists. Numerical results, especially for chains having two types of exchange bonds, are presented and discussed.