The Vibration-Rotation-Tunneling Levels of N2–H2O and N2–D2O
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Authors
Wang, Xiao-Gang
Carrington, Tucker Jr
Date
2015-03-30
Type
journal article
Language
en
Keyword
Vibration , Rotation , Tunneling Levels , N2–H2O , N2–D2O
Alternative Title
Abstract
In this paper, we report vibration-rotation-tunneling levels of the van der Waals clusters N2–H2O and
N2–D2O computed from an ab initio potential energy surface. The only dynamical approximation
is that the monomers are rigid. We use a symmetry adapted Lanczos algorithm and an uncoupled
product basis set. The pattern of the cluster’s levels is complicated by splittings caused by H–H
exchange tunneling (larger splitting) and N–N exchange tunneling (smaller splitting). An interesting
result that emerges from our calculation is that whereas in N2–H2O, the symmetric H–H tunnelling
state is below the anti-symmetric H–H tunnelling state for both K = 0 and K = 1, the order is reversed
in N2–D2O for K = 1. The only experimental splitting measurements are the D–D exchange tunneling
splittings reported by Zhu et al. [J. Chem. Phys. 139, 214309 (2013)] for N2–D2O in the v2 = 1
region of D2O. Due to the inverted order of the split levels, they measure the sum of the K = 0 and
K = 1 tunneling splittings, which is in excellent agreement with our calculated result. Other splittings
we predict, in particular those of N2–H2O, may guide future experiments.