Rotationally Resolved Spectrum of the A(2)A'' -X(2)A'' 0(0)(0) Band of 1-Indanyl Radical

The rotationally resolved spectrum of the A(2)A'' X(2)A'' 0(0)(0) band of jet-cooled 1-indanyl near 473 nm is recorded by laser induced fluorescence with a spectral resolution of similar to 0.014 cm(-1). Accurate spectroscopic constants for both A(2)A'' and X(2)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(pi) electron that stabilizes the 1-indanyl radical is discussed.