Vibrational Predissociation Spectra of C₂N⁻ and C₃N⁻: Bending and Stretching Vibrations

Abstract

We present infrared predissociation spectra of C2N−(H2) and C 3N−(H2) in the 300–1850 cm−1 range. Measurements were performed using the FELion cryogenic ion trap end user station at the Free Electron Lasers for Infrared eXperiments (FELIX) laboratory. For C2N−(H2), we detected the CCN bending and CC−N stretching vibrations. For the C3N−(H2) system, we detected the CCN bending, the CC−CN stretching, and multiple overtones and/or combination bands. The assignment and interpretation of the presented experimental spectra is validated by calculations of anharmonic spectra within the vibrational configuration interaction (VCI) approach, based on potential energy surfaces calculated at explicitly correlated coupled cluster theory (CCSD(T)‐F12/cc‐pVTZ−F12). The H2 tag acts as an innocent spectator, not significantly affecting the C2,3N− bending and stretching mode positions. The recorded infrared predissociation spectra can thus be used as a proxy for the vibrational spectra of the bare anions.

Zero-Point-Energy Driven Isotopic Exchange of the [H3O]− anion Probed by Mid-Infrared Action Spectroscopy

“…More precise theoretical predictions can be expected for a better description of the PES together with variational solutions to the vibrational Schrödinger equation. In this respect, we calculated an n -mode PES with up to 4-mode couplings to perform VSCF/VCI calculations for HOH·H – , similar to our previous studies on anionic systems (Cl – ·H 2 , C 2 N – and C 3 N – ),…”

Influence of Metal Identity in Bipyridine-Based Metal-4N Complexes With Formate

“…In addition, cryogenic preparation of the target ions allows suppression of thermal broadening. Cryogenic ion vibrational spectroscopy (CIVS) has been used to great success by many groups − and today represents a powerful part of the toolbox of cold chemistry.…”