The emission line shifts of the resonance transitions (s <- p) of Rb and Cs embedded in liquid He environment have been estimated using CASPT2 with quadruple-zeta basis sets. The liquid He environment has been approximated by a spherically symmetric model cluster, with 14 He atoms placed in equidistant positions from the central alkali atom. The emission line for the D1 transition is found to be blue shifted. The shift is estimated to be -1.2 to -1.8 nm for Rb and -2.2 to -2.6 nm for Cs, in very good agreement with the experimental estimates of -1.2 nm and -2.1 nm respectively obtained in liquid He. (C) 2016 Elsevier B.V. All rights reserved.