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  • A Fermi resonance and a parallel-proton-transfer overtone in the Raman spectrum of linear centrosymmetric N4H+: A polarizability-driven first principles molecular dynamics study
Title: A Fermi resonance and a parallel-proton-transfer overtone in the Raman spectrum of linear centrosymmetric N4H+: A polarizability-driven first principles molecular dynamics study
We present molecular dynamics (MD), polarizability driven MD (α-DMD), and pump–probe simulations of Raman spectra of the protonated nitrogen dimer N4H+, and some of its isotopologues, using the explicitly correlated coupled-cluster singles and doubles with perturbative triples [CCSD(T)]-F12b/aug-cc-pVTZ based potential energy surface in permutationally invariant polynomials (PIPs) of Yu et al. [J. Phys. Chem. A 119, 11623 (2015)] and a corresponding PIP-derived CCSD(T)/aug-cc-pVTZ-tr (N:spd, H:sp) polarizability tensor surface (PTS), the latter reported here for the first time. To represent the PTS in terms of a PIP basis, we utilize a recently described formulation for computing the polarizability using a many-body expansion in the orders of dipole–dipole interactions while generating a training set using a novel approach based on linear regression for potential energy distributions. The MD/α-DMD simulations reveal (i) a strong Raman activity at 260 and 2400 cm−1, corresponding to the symmetric N–N⋯H bend and symmetric N–N stretch modes, respectively; (ii) a very broad spectral region in the 500–2000 cm−1 range, assignable to the parallel N⋯H+⋯N proton transfer overtone; and (iii) the presence of a Fermi-like resonance in the Raman spectrum near 2400 cm−1 between the Σg+ N–N stretch fundamental and the Πu overtone corresponding to perpendicular N⋯H+⋯N proton transfer.  more » « less
Award ID(s):
1855583
PAR ID:
10473174
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Wiley
Date Published:
Journal Name:
The Journal of Chemical Physics
Volume:
157
Issue:
15
ISSN:
0021-9606
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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