Photodissociation spectroscopy of Mg+H2O

✍ Scribed by C.S. Yeh; K.F. Willey; D.L. Robbins; J.S. Pilgrim; M.A. Duncan

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 398 KB
• Volume: 196
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(92)85960-i

✦ Synopsis

Mg+-H20 ion-molecule complexes are produced in a pulsed supersonic nozzle cluster source. These weakly bound complexes are mass selected and studied with laser photodissociation spectroscopy in a reflectron time-of-flight mass spectrometer system. An electronic transition assigned as 2B2--}X 2A1 is observed with an origin at 28399 cm -1 (vac). The spectrum has a prominent progression in the metal-H20 stretching mode with a frequency (to'c) of 517.1 cm-t. An extrapolation of this progression fixes the excited state dissociation energy (D0) at 16008 cm -~. The corresponding ground state value (D~) is 8732 cm -~ (25.0 kcal/ mol ). The solvated bending mode and asymmetric stretching mode of water are also active in the complex. A second electronic transition assigned as 2B l ~-X 2A 1 is observed with an origin at 30386 cm-t and a metal stretch frequency of 483.4 cm-t. This study was guided by ab initio calculations by Bauschlicher and co-workers, which provide accurate predictions of the electronic transition energies, vibrational constants and dissociation energies.