Photoionization mass spectrometry of kinetic energy-selected ions. An ion retarding potential difference method applied to NO+ and O+ from N2O

Abstract

A new method is described to obtain photoionization efficiency curves of kinetic energy-selected fragment ions. The method is tested and discussed in the case of the dissociative photoionization yields of NO + and O + from N 2 O. The attention is focussed on the dissociative autoionization processes in the threshold region, in the FranckCondon region of the N 2 O (à 2 Σ + ) state and in the Franck-Condon gap between the à 2 Σ + and 2 Π states.

Absolute electron impact ionization cross sections for N2O and NO from threshold up to 1000 eV

“…In the lower E and D regions it undergoes reactions [Krankowsky et al, 1987; National Bureau of Standards, 1975] with other atmospheric gases and plays an important role in the clustering of proton hydrates. Since NO + can result from the ionization of NO and dissociative ionization of N20, many studies [Elan& 1973;Brehm et al, 1974;Nenner et al, 1980;Olivier et al, 1982;Ibuki and Sugita, 1984;Olivier et al, 1984;Hamdan et al, 1987;Locht et al, 1991;Takahashi et al, 1991] have been directed toward photon and electron impact ionization and fragmentation properties of these molecules. However, to date, there have been a very few measurements on the electron impact ionization and dissociative ionization cross sections of them which are important for modeling the Earth's ionosphere.…”

Photoionization mass spectrometry of kinetic energy-selected ions. The translational energy distribution of N+ /N2 in the inner-shell ionization energy range

“…The main goal of this work was to apply the ion retarding potential difference (IRPD) method [9] to resonance phenomena to obtain translational energy distributions at several wavelengths. In the case of N + /N 2 the dissociative ionization in the inner-shell ionization energy region has been extensively investigated [2][3][4][5][6][7][8].…”

“…The experimental setup used in this photoionization work has been described elsewhere [9,11] and only the most salient features will be repeated here.…”

“…To study dissociative photoionization processes, a new method has recently been proposed [9]. It is mainly based on (i) fragment ions translational energy distribution measurements by means of a retarding potential method and (ii) ionization efficiency curves measurements for preset retarding potential settings.…”

Dissociative photoionization of N2O in the region of the N2O+(B 2Π) state studied by ion–electron velocity vector correlation

“…10 The role of bending in the dissociation process of the N 2 O ϩ (B 2 ⌸) state is also invoked in a recent theoretical study of the predissociation mechanisms of the A 2 ⌺ ϩ and B 2 ⌸ states of N 2 O ϩ . 18 Investigations of the kinetic energy distribution or kinetic energy releases of the photoions in TPEPICO studies, 16 mass spectrometry of kinetic energy selected ions, 19 or PEPICO spectroscopy at fixed wavelengths 20 have lead to the attribution of dissociation limits populated by DPI via the B state. To our knowledge, the previously reported angular information about these DPI processes concern the angle resolved photoelectron spectroscopy of N 2 O in the 14 -70 eV photon energy range 21 which shows that the ␤ e asymmetry parameter for ionization of the 1 orbital increases significantly with the ionization energy, varying from 0.08 to 0.32 in the 18 -21 eV presently explored photon energy range.…”