Ro-vibrationally averaged structure of 2Π NCS: Re-interpretation of the B0 values

Hirano, Tsuneo

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https://hdl.handle.net/2142/100728 Copy

Description

Title

Ro-vibrationally averaged structure of 2Π NCS: Re-interpretation of the B0 values

Author(s)

Hirano, Tsuneo

Contributor(s)

• Jensen, Per
• Nagashima, Umpei

Issue Date

2018-06-18

Keyword(s)

Mini-symposium: New Ways of Understanding Molecular Spectra

Abstract

We have constructed ab initio 3D potential energy surfaces (PESs) for X˜ 2Π NCS in core-valence SDCI+Q/[aCVQZ(N,C,S)] calculations. The B0 value predicted from these PESs deviates only 0.05% from the corresponding experimental values for NC32S and NC34S. Since we have quite accurate 3D PESs, we can determine both the equilibrium structure and the r0 structure accurately: re(N–C) = 1.1778 A, ˚ re(C–S) = 1.6335 A, and ˚ 6 e(N–C–S) = 180◦ . The ro-vibrationally averaged structure, determined as expectation values over DVR3D wavefunctions, has hr(N–C)i0 = 1.1836 A, ˚ hr(C–S)i0 = 1.6356 A, and ˚ h6 (N–C–S)i0 = 172.5◦ . The 3D PESs show that the X˜ 2Π NCS has its potential energy minimum at a linear configuration, and hence it is a “linear molecule.” Experimentally, B0 values are reported for two isotopologues only.a Using the expectation values given above as the initial guess, a bent r0 structure having an h6 (N–C–S)i0 of 172.2◦ is deduced from the experimentally reported B0 values for NC32S and NC34S. It shows that the linear molecule NCS has a “bent” ro-vibrationally averaged structure, confirming our previous predictions: b any linear molecule is observed as being bent on ro-vibrational average. See Ref. c c for further discussion of this molecule. 2Π NCS is a typical Renner molecule. The Renner spectroscopy of this molecule will be presented in a separate talk.d

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100728

DOI

10.15278/isms.2018.MH09

Copyright and License Information

Copyright 2018 Tsuneo Hirano

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