| Autor: |
Koner, Debasish, Schwilk, Max, Patra, Sarbani, Bieske, Evan J., Meuwly, Markus |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 7/28/2020, Vol. 153 Issue 4, p1-12, 12p, 8 Diagrams, 2 Charts, 2 Graphs |
| Abstrakt: |
The fundamental vibrational frequencies and higher vibrationally excited states for the N 3 + ion in its electronic ground state have been determined from quantum bound state calculations on three-dimensional potential energy surfaces (PESs) computed at the coupled-cluster singles and doubles with perturbative triples [CCSD(T)]-F12b/aug-cc-pVTZ-f12 and multireference configuration interaction singles and doubles with quadruples (MRCISD+Q)/aug-cc-pVTZ levels of theory. The vibrational fundamental frequencies are 1130 cm−1 (ν1, symmetric stretch), 807 cm−1 (ν3, asymmetric stretch), and 406 cm−1 (ν2, bend) on the higher-quality CCSD(T)-F12b surface. Bound state calculations based on even higher level PESs [CCSD(T)-F12b/aug-cc-pVQZ-f12 and MRCISD+Q-F12b/aug-cc-pVTZ-f12] confirm the symmetric stretch fundamental frequency as ∼1130 cm−1. This compares with an estimated frequency from experiment at 1170 cm−1 and previous calculations [Chambaud et al., Chem. Phys. Lett. 231, 9–12 (1994)] at 1190 cm−1. The remaining disagreement with the experimental frequency is attributed to uncertainties associated with the widths and positions of the experimental photoelectron peaks. Analysis of the reference complete active space self-consistent field wave function for the MRCISD+Q calculations provides deeper insight into the shape of the PES and lends support for the reliability of the Hartree–Fock reference wave function for the coupled cluster calculations. According to this, N 3 + has a mainly single reference character in all low-energy regions of its electronic ground state (3A″) PES. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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