EPJ Web of Conferences 84, 03004 (2015)
https://doi.org/10.1051/epjconf/20158403004

Indirect predissociation of highly excited singlet states of N₂

¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
² Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
³ Department of Physics, Wellesley College, Wellesley, Massachusetts 02481, USA
⁴ Synchrotron Soleil, Orme des Merisiers, St. Aubin, BP. 48, 91192 Gif-sur-Yvette Cedex, France

^a Corresponding author: heays@strw.leidenuniv.nl

Published online: 29 January 2015

Abstract

Indirect predissociation of the b′ ¹Σ_u⁺(v = 20) level of N₂ is studied experimentally by vacuum-ultraviolet photoabsorption employing synchrotron radiation and a Fourier-transform spectrometer, and interpreted with the aid of a quantitative model of interacting ¹Π_u and ¹Σ_u⁺, bound and unbound states which solves the coupled Schrödinger equation. An observed rotationally-localised peak in the b′(20) predissociation linewidths is identified by the model as arising from an interaction with a strongly predissociated and unobserved bound level of the mixed c₃ ¹Π_u and o₃ ¹Π_u Rydberg states. This leads to the dissociation of b′(20) into the continuum of the b ¹Π_u valence state. The residual observed predissociation of b′ ¹Σ_u⁺(v = 20) apart from the rotationally-localised peak cannot be explained by a mechanism of ¹Π_u and ¹Σ_u⁺ interaction, and must involve states of higher multiplicity.