An original scheme has been developed to compute, fully analytically, the Hartree-Fock Young modulus (second derivative of the Hartree-Fock energy with respect to the unit cell length) of stereoregular polymers. The evaluation of the elastic modulus is performed without the use of any intercell coordinate. The direct and efficient computation of the Young modulus requires the evaluation of the full Hessian (including cell and mixed components), and, subsequently, some specific integral derivatives and the use of a seven-step coupled-perturbed Hartree-Fock procedure. The long-range effects related to the Young modulus (and other second-order derivatives associated with vibrational frequencies) are evaluated by using a technique based on multiple Taylor expansions. The implementation of the integral derivatives in the McMurchie and Davidson framework is described in detail. Two examples show that the stability and accuracy of the technique proposed are excellent. (C) 2003 American Institute of Physics.