Using high-resolution Fourier transform spectra of monoisotopic (H2Se)-Se-80 recorded in the 1.8- and 1.55-mu m regions, an extensive analysis of the 2 nu(1) + nu(2), nu(1) + nu(2) + nu(3), 3 nu(1), 2 nu(1) + nu(3), and nu(1), + 2 nu(3) bands of this molecule has been performed, leading to a precise set of rotational levels for its {(210), (111)} and {(300), (201), (102)} vibrational states. For the first set of states, it was necessary to introduce the undetected (012) state in the Hamiltonian model, and the observed levels of {(210), (111)} were least-squares fit using a Hamiltonian which takes explicitly into account both the Coriolis interactions between the levels of(210) and(111) and of(111)and (012), and the Darling-Dennison interaction between the levels of(210) and (012). For the second set of states, namely, {(300), (201), (102)}, the same type of situation occurs and it was necessary as well to introduce in the model the (003) vibrational state. In this way, all the experimental levels of {(210), (111)}, and {(300), (201), (102)} were calculated almost to within their experimental uncertainties and a precise set of vibrational energies and rotational and coupling constants was derived with the band centers nu(0) (2 nu(1) + nu(2)) = 5612.7107, nu(0)(nu(1) + nu(2) + nu(3)) = 5613.7546, nu(0) (3 nu(1)) = 6953.4607, nu(0) (2 nu(1) + nu(3)) = 6798.2084, and nu(0) (nu(1) + 2 nu(3))= 6798.0967 cm(-1). (C) 1994 Academic Press, Inc.