Article

# Calibration-quality adiabatic potential energy surfaces for H-3(+) and its isotopologues

Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.

The Journal of Chemical Physics (Impact Factor: 2.95). 05/2012; 136(18):184303. DOI: 10.1063/1.4711756 Source: PubMed

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Attila Csaszar, Mar 11, 2014 Available from: Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

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**ABSTRACT:**For high-precision calculations of rovibrational states of light molecules, it is essential to include non-adiabatic corrections. In the absence of crossings of potential energy surfaces, they can be incorporated in a single surface picture through coordinate-dependent vibrational and rotational reduced masses. We present a compact method for their evaluation and relate in particular the vibrational mass to a well defined nuclear core mass derived from a Mulliken analysis of the electronic density. For the rotational mass we propose a simple, but very effective parametrization. The use of these masses in the nuclear Schrödinger equation yields numerical data for the corrections of a much higher quality than can be obtained with optimized constant masses, typically better than 0.1 cm(-1). We demonstrate the method for H(2), H(2) (+), and singly deuterated isotopologues. Isotopic asymmetry does not present any particular difficulty. Generalization to polyatomic molecules is straightforward.The Journal of Chemical Physics 10/2012; 137(16):164316. DOI:10.1063/1.4762442 · 2.95 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**Potential energy surfaces are obtained for singlet $\rm H_3^+$ in magnetic fields of up to 2350 T. The magnetic interaction was treated by first order perturbation theory and the interaction terms computed {\em ab initio}. They were then fitted to a functional form and added to a recent, highly accurate adiabatic potential energy surface. In its most stable orientation, the molecule is arranged such that the magnetic field vector is in the molecular plane. The most stable configuration is no longer $D_{3h}$ as in the field-free case, but $C_{2v}$, though the stabilization energy is extremely small, of the order of 0.01 $\rm cm^{-1}$ for a 2350 T field. Finally, we have calculated, for a range of magnetic field strengths and orientations, all the vibrational eigenvalues which are below the barrier to linearity in the field-free case.The Journal of Physical Chemistry A 03/2013; 117(39). DOI:10.1021/jp312856s · 2.69 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**We have used a Lanczos algorithm with a nondirect product basis to compute energy levels of \hhh with $J$ values as large as 46. Energy levels computed on the potential surface of M.~Pavanello, \ea (\JCP {136}{184303}{2012}) agree well with previous calculations for low $J$ values.The Journal of Physical Chemistry A 03/2013; 117(39). DOI:10.1021/jp312027s · 2.69 Impact Factor