The dependence of the nuclear energy on the deformation parameters of order two and three is investigated for some s–d shell nuclei. A Hartree–Fock technique is used to calculate the stiffness parameters for quadrupole and octupole deformations. The nuclei most soft under quadrupole and octupole deformations are seen to be 30Si and 38Ar, respectively. The reduced E3 transition rates are calculated and are compared with available experimental results.