The photodissociation spectrum of SO+2

Abstract

The photodissociation spectrum of SO+2 corresponding to the process SO+2 +hν→SO++O has been measured on a triple quadrupole system for the wavelength ranges: 3000–3400 and 4400–5120 Å. The spectrum in the visible has been assigned to the C̃ 2B1←Ã 2A2 transition and vibrational structure analyzed to yield λ00=4187 Å, the harmonic vibrational frequencies ν̃′1=953 cm−1, ν̃′′2=499 cm−1, ν̃′1=767 cm−1, and ν̃2 =410 cm−1, and the anharmonicity constants X″11 =−6.3 cm−1, X′′12 =−6.1 cm−1, X″22 =−4.2 cm−1, X12 =−6.3 cm−1, and X′22 =−7.4 cm−1. Apparent photodissociation cross sections ranged from ∼1×10−20–1.6×10−19 cm2 in the visible spectrum. In the UV spectrum the highly congested vibrational structure could not be resolved sufficiently for analysis; photodissociation cross sections ranged from ∼2–4×10−19 cm2 with broad bands roughly corresponding to expected progression in ν1 and ν′2 within the C̃ 2B1←X̃ 2A1 electronic transition. The process SO+2 +hν→S++O2 showed an onset near 3108 Å and the corresponding photodissociation spectrum showed sufficient vibrational structure to yield ν̃′′2∼454 cm−1, ν̃′1 ∼955 cm−1, and ν̃2 ∼411 cm−1. This new process, which had σ≤3×10−20 cm2, was proposed to result from the D̃ 2B2←X̃ 2A1 transition. Several new photodissociation cross section measurements on N2O+ have also been made in the vicinities of 3381 and 4880 Å, taking advantage of the high sensitivity (→10−21 cm2) of the triple quadrupole system.