An accurate analytic representation for the Bloch-Gruneisen integral

An analytic representation for the Bloch-Gruneisen integral, describing the electron-photon interaction contribution to the electrical resistivity of metals, is presented. The representation takes the form of an originally infinite series, truncated to K terms. The approximation is highly accurate yielding relative errors less than 1% for even a single term (K=1) for T<or= theta /4 and less than 0.1% with K=20 for all T<or=10 theta , where theta is the Debye temperature. The series approximation is shown to be superior to the previously suggested ninth-order polynomial in log( theta /T). Two other infinite series approximations are also discussed.