Rotationally resolved spectrum of the A² A″-X² A″ 000 band of 1-indanyl radical

The rotationally resolved spectrum of the A2 A″- X2 A″ [Formula: see text] band of jet-cooled 1-indanyl near 473 nm is recorded by laser induced fluorescence with a spectral resolution of ~0.014 cm−1. Accurate spectroscopic constants for both A2 A″ and X2 A″ states of 1-indanyl are determined from rotational analysis of the experimental spectrum. These indicative spectroscopic parameters are applied to test the calculated structure of 1-indanyl. The calculations show good agreements with the experimental data. Based on the computational molecular orbitals and spin densities for 1-indanyl, the delocalization of unpaired p π electron that stabilizes the 1-indanyl radical is discussed.