Potential surfaces for the Rydberg states of H3

The Jahn–Teller effect in the 3 pe ′ Rydberg state of H 3 : review of experimental and ab initio determinations

“…It is instructive to compare the JT terms for n = 3 from table 2 with those derived from high-resolution emission spectroscopy in the 1980s [11,12], as well as with those derived previously by various authors from quantum-chemical potential surfaces [6,7,8,18]. This requires converting the definitions and coordinates used in previous papers to the ones used here.…”

“…This work was soon followed by the computations of Nager & Jungen [8], who used their frozen-core Rydberg ab initio method to predict numerous Rydberg states over a wide range of geometries. More recent potential surfaces of H 3 Rydberg states have been published in Mistrík et al [6] and Galster et al [19].…”

“…The ab initio work on excited states of H 3 and H + 3 has been reported alternatively in terms of Dykstra coordinates [6,8,21], hyperspherical coordinates [19] or mass-scaled Jacobi coordinates [22]. In all these papers, the relationships between coordinates employed and the straightforward bond-length coordinates R 1 , R 2 , R 3 have been spelled out in detail.…”

“…The theory presented in Kokoouline et al [1] and dos Santos et al [2] is based on ab initio computations of bound n = 4 Rydberg states of H 3 by Mistrík et al [6], from which the static linear JT splitting was extracted, using a procedure initiated by Staib & Domcke [7] (who based their work on earlier ab initio computations of Nager & Jungen [8] for n = 3). This information then subsequently served to compute the dynamical electron capture process by the positive ion, followed by neutral molecular dissociation [2].…”

“…We also attempt to redetermine the linear and quadratic JT splitting constants on the basis of the most sophisticated ab initio H 3 3pe potential surfaces existing to date. Although King & Morokuma [18] extracted a quadratic JT constant from their ab initio surface, to date, no quadratic constant for the later ab initio surfaces [6,8,19] has been reported; similarly, no quadratic constant has been extracted from the spectroscopic data of Herzberg et al [11,12]. While we focus in this work on the 3pe state of H 3 , we also consider the n = 4 and n = 5 members of the npe Rydberg series, for which ab initio potential energy surfaces also exist [6]; consideration of these surfaces provides information on the energy dependences of the quantum defect parameters.…”