The two-photon spectrum and polarization ratio of biphenylene have been measured at room temperature in the spectral range 225-370 nm, combining fluorescence-excitation and thermal-lensing techniques. The first excited Agstate 2Ag, has been observed around 265 nm and the second excited B1g, 2B1g, has its onset at ≈ 225 nm. Similarities and differences with alternant aromatics are pointed out. MO calculations of two-photon intensities support the interpretation of the experimental data. © 1990.
Bich, V. T., Bini, R., Salvi, P. R., & Marconi, G. (1990). Two-photon spectroscopy of antiaromatic molecules: the case of biphenylene. Chemical Physics Letters, 175(5), 413–418. https://doi.org/10.1016/0009-2614(90)85556-R