Spectra of Matrix-Isolated NiF2 and NiCl2

Abstract

The infrared (400–4000‐cm⁻¹) and ultraviolet (5000–2200‐Å) absorption spectra of NiF₂ and NiCl₂ molecules isolated in an Ar matrix at 14°K have been observed. Sharp systems of absorptions near 780 cm⁻¹ for NiF₂ and 520 cm⁻¹ for NiCl₂ can be assigned to the antisymmetric stretching fundamental of the isolated molecules. Most of the vibrational splittings of the more abundant isotopic species have been resolved. Absorptions due to dimers and to other as yet uncharacterized species also appear. Evidence supports the hypothesis that NiF₂ and NiCl₂ are linear. No ultraviolet absorptions have been observed for NiF₂, but the intense absorption previously observed for NiCl₂ between 3650 and 2750 Å has been found to have extensive vibrational structure, probably contributed by the symmetric stretching mode of the upper state.