We consider a nonlinear problem on R^N in dimension N ≥ 2. Here g is a superlinear, subcritical, possibly nonhomogeneous, odd nonlinearity. We deal with the case where the associated functional is not bounded below on the L^2-unit sphere, and we show the existence of infinitely many solutions.
Bartsch, T., & de Valeriola, S. (2012). Normalized solutions of nonlinear Schrödinger equations. Archiv der Mathematik, 100(1), 75-83. https://doi.org/10.1007/s00013-012-0468-x (Original work published 2012)