Polarized Reflection and Absorption Spectra of the [2.2]-Paracyclophane Crystal

The reflection spectra of a [2.2]-paracyclophane crystal were measured in the 17000–62000 cm−1 region with incident light polarized parallel and perpendicular to the a-axis. From analysis of the reflection spectra by the Kramers-Kronig method, the a-axis and c-axis polarized absorption spectra in the 38000–60000 cm−1region were obtained. The c-axis polarized spectrum was obtained for the first time. The 43000 cm−1 band in the c-axis spectrum was assigned to the transitions to the 1B1u(p) and 1B1u (CT) states. The band around 48000 cm−1 was assigned to the transition to the 1B3u-state, corresponding to the transition to the 1E2g -state in benzene.