New look at perturbations in the N₂(C³ 3Πu, υ) electronic state. Indirect predissociation through states C''Π_u and1 Σ_u+ states

Author(s)

Ventura, Laiz R. ; da Silva, Ramon S. ; Amorim, Jayr ; Fellows, Carlos E.

• Document type: Journal article
• Source: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY; v. 336, p. 9-pg., 2025-08-05.

Abstract

To address a puzzle that has persisted for nearly 90 years, this work presents new evidence on the phenomenon of indirect predissociation in the N2 molecule, focusing specifically on the C3-B3electronic transition, known as the Second Positive System. A high-resolution experimental analysis of C3-B3emissions is complemented by high-level ab initio calculations of spin-orbit coupling matrix elements as a function of the interatomic distance. Together, these approaches provide comprehensive insights into the predissociation phenomenon observed in the molecular nitrogen spectrum. The mixing of the N2 (C '' 5) state with the N2 (C3) state, exhibiting a high spin-orbit coupling of approximately 40 cm-1, significantly influences the emission of the second positive (C3-B3) and Herman infrared (C '' 5-A ' 5) band systems. Additionally, the 17 + state, with a strong spin-orbit coupling with N2 (C '' 5), plays a crucial role in enabling indirect predissociation, leading to the formation of two N(4) atoms. This study provides a crucial step in understanding the indirect predissociation phenomenon in N2 spectroscopy. (AU)

• FAPESP's process: 23/08074-5 - New experimental and theoretical investigations about the molecular ion N2+
• Grantee: Laiz Rodrigues Ventura
• Support Opportunities: Scholarships in Brazil - Post-Doctoral