An efficient grid calculation of vibrational states for H3∗ with geometric phase in hyperspherical coordinates

We report the J=0 calculations of vibrational energy levels of the first excited state of H3 with the consideration of geometric phase effects. A pseudo-spectral technique and a mixed grid and nondirect product basis method have been used in hyperspherical coordinates. The action of the Hamiltonian on the wavefunction is performed by the fast Fourier transform for ρ and φ variables and the pseudo-inverse DVR-FBR transform for θ. The nondirect product hyperspherical harmonics describe correctly the boundary conditions of vibrational states at θ=0.