Effect of bulk magnetic field on critical Ising films

Two-dimensional Ising films Lx infinity in a nonvanishing bulk magnetic fie ld H are studied at the bulk critical temperature T-c for two choices of su rface fields (a) H-1=H-L=0 (ordinary transition), and (b) H-1=H-L=infinity (normal transition) by the density-matrix renormalization-group method. Uni versal scaling functions for magnetization profiles, the excess magnetizati on Gamma, the longitudinal correlation length xi parallel to, and for the a nalog of the solvation force f(solv) are found and discussed. When H-1=0 th e scaling function for f(solv) has two symmetric minima at y = sgn(H)L\H\ ( v/Delta) approximate to +/- 1 with an amplitude at the minimum about 3.8 ti mes the value at H=0, the Casimir amplitude. For the normal transition the scaling function for f(solv) has a single minimum near the continuation of the pseudocoexistence (capillary condensation) line, with an amplitude abou t 100 times the Casimir amplitude.