Electronic Journal of Differential Equations, Vol. 2004(2004), No. 62, pp. 1-16. Title: Modified wave operators for nonlinear Schrodinger equations in one and two dimensions Authors: Nakao Hayashi (Osaka Univ., Japan) Pavel I. Naumkin (UNAM Campus Morelia, Mexico) Akihiro Shimomura (Gakushuin Univ., Tokyo, Japan) Satoshi Tonegawa (Nihon Univ., Tokyo, Japan) Abstract: We study the asymptotic behavior of solutions, in particular the scattering theory, for the nonlinear Schr\"{o}dinger equations with cubic and quadratic nonlinearities in one or two space dimensions. The nonlinearities are summation of gauge invariant term and non-gauge invariant terms. The scattering problem of these equations belongs to the long range case. We prove the existence of the modified wave operators to those equations for small final data. Our result is an improvement of the previous work [13] Submitted March 10, 2004. Published April 21, 2004. Math Subject Classifications: 35Q55, 35B40, 35B38 Key Words: Modified wave operators; nonlinear Schrodinger equations