Absorptions between 3000 and 5500 cm(-1) of cyclic O4+ and O4- trapped in solid neon.

Recently, gas-phase absorptions in the 3000-4300 cm(-1) spectral region have been assigned to combination bands built on (ν1 + ν5) of ground-state cyc-O4(+). Other gas-phase experiments identified an electronic transition of cyc-O4(-) complexed with an argon atom between 4000 and 5300 cm(-1). Absorptions that correspond closely to these two groups of bands have been observed in neon-matrix experiments in which both cyc-O4(+) and cyc-O4(-) are trapped at 4.3 K in solid neon. The results are compared with the gas-phase data, and the proposed assignments are considered by taking into account the results of isotopic substitution.