JMSSJ On-line

JMSSJ On-line, Vol. 43 (1995) No. 5, pp. 257-263

Isotope Effect in the Photodissociation of Ammoniated Ammonium Ions by CO₂ Laser		>> Full Text PDF >> References
*Yasumasa IKEZOE,^a Takeshi SOGA,^a Kazuya SUZUKI,^a and Shin-ichi OHNO^b** ^a Japan Atomic Energy Research Institute (Tokai-mura, Ibaraki 319-11, Japan)* ^b Tokai University (Tomigaya 2-28, Shibuya-ku, Tokyo 113, Japan)

CO₂ laser induced photodissociations of NH₄⁺·nNH₃ and of ND₄⁺·nND₃ were examined by a tandem mass spectrometer (TMS). Photodissociation took place for NH₄⁺·nNH₃ with n≥5. No photodissociation was observed for ND₄⁺·nND₃. It depended on the laser intensity, wave number, and cluster size. The maximum yield of NH₄⁺·5NH₃ dissociation was obtained at 1080 cm^-1, and that of NH₄⁺·7NH₃ shifted to 1075 cm^-1. Two molecules dissociation was observed in addition to one molecule dissociation. The yield of one molecule dissociation increased linearly with the laser intensity, indicating that the dissociation is a single photon process. Elementary processes which affect isotope effect in the dissociation are discussed.

Key words: Photodissociation, Isotope effect, Ammonia cluster ion, Tandem mass spectrometer, CO₂ laser