The infrared spectra of BF3+ and BF2OH+ trapped in solid neon

Abstract

Observations on a Ne:BF(3) = 400:1 mixture into which a trace of normal or isotopically enriched water had been introduced, codeposited at 4.3 K with a beam of neon atoms that had been excited in a microwave discharge, demonstrate that a pair of absorptions at 1662 cm(-1) and 1722 cm(-1) that were previously assigned to the two boron-isotopic species of BF(3)(+) should be reassigned to a BF(2) stretching fundamental of BF(2)OH(+). The OH stretching fundamental of that product was identified for the first time at 3240 cm(-1). The degenerate BF(3) stretching fundamental of (11)BF(3)(+) appears at an unusually high frequency, 1790 cm(-1), consistent with strong pseudo-Jahn-Teller interaction of that ground-state fundamental with the B̃(2)E(') electronic state, as predicted by theory. The recent availability of detailed ab initio and density functional calculations of the vibrational fundamentals of BF(2)(-) and BF(3)(-) facilitates assignment of the infrared absorptions of those two products.