Resonant states of the H3(­) molecule and its isotopologues D2H­ and H2D­.

Using the ground potential energy surface [Ayouz, M.; etal. J. Chem. Phys. 2010, 132, 194309] of the H3(­) molecule, we have determined the energies and widths of the complex resonant levels of H3(­) located up to 4000 cm(­1) above the dissociation limit H­ + H2(νd = 0,jd = 0). Bound and resonant levels of the H2D­ and D2H­ isotopologues have been also characterized within the same energy range. The method combines the hyperspherical adiabatic approach, slow variable discretization method, and complex absorbing potential. These results represent the first step for modeling the dynamics of the associated diatom­negative ion collision at low energy involving rotational quenching of the diatom and reactive nucleus exchange via the weak tunneling effect through the potential barrier of the potential energy surface.

Potential energy and dipole moment surfaces of HCO- for the search of H- in the interstellar medium.

Potential energy and permanent dipole moment surfaces of the electronic ground state of formyl negative ion HCO(-) are determined for a large number of geometries using the coupled-cluster theory with single and double and perturbative treatment of triple excitations ab initio method with a large basis set. The obtained data are used to construct interpolated surfaces, which are extended analytically to the region of large separations between CO and H(-) with the multipole expansion approach. We have calculated the energy of the lowest rovibrational levels of HCO(-) that should guide the spectroscopic characterization of HCO(-) in laboratory experiments. The study can also help to detect HCO(-) in the cold and dense regions of the interstellar medium where the anion could be formed through the association of abundant CO with still unobserved H(-).

Potential energy and dipole moment surfaces of H(3) (-) molecule.

A new potential energy surface for the electronic ground state of the simplest triatomic anion H(3) (-) is determined for a large number of geometries. Its accuracy is improved at short and large distances compared to previous studies. The permanent dipole moment surface of the state is also computed for the first time. Nine vibrational levels of H(3) (-) and 14 levels of D(3) (-) are obtained, bound by at most approximately 70 and approximately 126 cm(-1), respectively. These results should guide the spectroscopic search of the H(3) (-) ion in cold gases (below 100K) of molecular hydrogen in the presence of H(-) ions.