Molecular ion fluorescence excitation spectrum from an ion beam

Ab initiocalculations of radiative transition probabilities in theX2Σ+andA2Π electronic states of CO+

“…Laser induced fluorescence experiments were reported by Bondybey and Miller [5], Brown et al [6], Danon et al [7] and very recently by Mahan and O'Keefe [8], Danon et al [7] trapped the ions in an ion cyclotron resonance cell, whereas in the experiments of Mahan and O'Keefe [8] the CO + ions were confined in the observation region by means of a radiofrequency quadrupole trap. In view of the experimental difficulties arising from the spacial dissipation of the ions, caused by their mutual electrostatic repulsion, the measured"lifetimes of all the above mentioned groups (With the exception of [6]) are in surprisingly good agreement. It has been found that the observed v' dependence of the lifetimes can be well reproduced within the Franck-Condon approximation [2,3,8], which implies that the electronic transition moment does not vary much in the investigated range of vibrational levels (v'=0-9).…”

“…M6hlmann and de Heer [3] measured the lifetimes for ten vibrational states using the delayed coincidence technique [4]. Laser induced fluorescence experiments were reported by Bondybey and Miller [5], Brown et al [6], Danon et al [7] and very recently by Mahan and O'Keefe [8], Danon et al [7] trapped the ions in an ion cyclotron resonance cell, whereas in the experiments of Mahan and O'Keefe [8] the CO + ions were confined in the observation region by means of a radiofrequency quadrupole trap. In view of the experimental difficulties arising from the spacial dissipation of the ions, caused by their mutual electrostatic repulsion, the measured"lifetimes of all the above mentioned groups (With the exception of [6]) are in surprisingly good agreement.…”

“…In particular, much effort has been devoted to the investigation of the fluorescence from the first excited A ~Yl state into the X 2y,+ ground state [2][3][4][5][6][7][8], which contributes to the visible emission of comet tails [9]. The first accurate lifetime measurements for the A 2II state were performed by Holland and Maier [2], who observed the fluorescence from a CO + ion beam at very low pressures.…”

Chapter 3. Gas-phase molecular spectroscopy

“…Although requiring long accumulation times, this technique is claimed to be more versatile than indirect beam methods, and has the advantage over static-sample direct methods of being collision free. 249 Studies of the electronic spectroscopy of larger ions have recently included detailed investigations of Jahn-Teller effects in substituted benzene cations,250 and have seen the application of LIF to similar species, both in the gas phase and in matrices. (The spectroscopy of ions in matrices has been reviewed by Andrews'.)…”

Symmetric charge-exchange reactions of N 2 + -ions investigated by laser-induced fluorescence

“…For the measurement of ionic species, the methods of laser-induced fragmentation [4] and laser-induced fluorescence [5,6] have been applied. The former method is very sensitive but is limited to molecular ions with pre-dissociating excited states.…”