Rovibrational dynamics of the quasistructural N2 dimer
Roland Tóbiás1,2, Csaba Fábri3, Marlene Bosquez4,5
1Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary. roland.tobias@ttk.elte.hu.
Communications Chemistry
|November 7, 2025
Summary
This study reveals the detailed structure and dynamics of the nitrogen dimer (N2)2 using advanced quantum chemistry. It identifies a planar, Z-shaped global minimum and calculates its dissociation energy and rovibrational states.
Area of Science:
- Physical Chemistry
- Chemical Physics
- Spectroscopy
Background:
- Experimental data on the nitrogen dimer (N2)2 is limited despite detailed knowledge of nitrogen gas absorption spectra.
- Understanding the van der Waals (vdW) dimer's properties is crucial for fundamental chemical physics.
Purpose of the Study:
- To explore the structural, dynamical, and rovibrational characteristics of the nitrogen dimer (N2)2.
- To provide definitive quantum chemical results with uncertainty estimates for the 14N2-14N2 isotopologue.
Main Methods:
- Development of three analytical representations of the dimer's ground-state potential energy surface (PES).
- Construction of two full-dimensional models of spectroscopic accuracy for the PES.
- Variational nuclear-motion computations for full- and reduced-dimensional systems.
Main Results:
- The global minimum of (N2)2 is confirmed as planar with a tilted, Z-shaped structure.
- Electronic dissociation energy is calculated as 109.3(26) cm-1; the first dissociation limit is estimated at 72.2(15) cm-1.
- Nearly 6000 bound rovibrational states and over 100 vibrational modes were computed for 14N2-14N2.
Conclusions:
- The nitrogen dimer (N2)2 is characterized as a quasistructural molecular complex.
- Isotopic substitution effects and spectral shifts/splittings of N≡N stretch fundamentals were analyzed.
- The study provides a comprehensive quantum chemical characterization of the nitrogen dimer.
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