The equations relating the q(2) J-type parameters of the matrix elements of the effective dipole-moment operator with the force field constants and the dipole-moment derivatives have been established by means of contact transformations in the case of nitrous oxide molecule. The effective dipole-moment operator corresponds to the reduced effective Hamiltonian derived by J.-L. Teffo, V. I, Perevalov, and O. M. Lyulin (J. Mel. Spectrosc. 168, 390-403 (1994)) for the global treatment of the vibrational-rotational energy levels of this molecule. Using these equations, the first and second derivatives of the dipole-moment function of the nitrous oxide molecule have been determined from the published values (O. M. Lyulin, V. I. Perevalov, and J.-L. Teffo, J. Mel. Spectrosc. 174, 566-580 (1995)) of the matrix element parameters of the effective dipole-moment operator. (C) 2001 Academic Press.