Spectroscopic characterization of the ground and low-lying electronic states of Ga2N via anion photoelectron spectroscopy

Abstract

Anion photoelectron spectra of Ga(2)N(-) were measured at photodetachment wavelengths of 416 nm(2.978 eV), 355 nm(3.493 eV), and 266 nm(4.661 eV). Both field-free time-of-flight and velocity-map imaging methods were used to collect the data. The field-free time-of-flight data provided better resolution of the features, while the velocity-map-imaging data provided more accurate anisotropy parameters for the peaks. Transitions from the ground electronic state of the anion to two electronic states of the neutral were observed and analyzed with the aid of electronic structure calculations and Franck-Condon simulations. The ground-state band was assigned to a transition between linear ground states of Ga(2)N(-)(X (1)Sigma(g) (+)) and Ga(2)N(X (2)Sigma(u) (+)), yielding the electron affinity of Ga(2)N, 2.506+/-0.008 eV. Vibrationally resolved features in the ground-state band were assigned to symmetric and antisymmetric stretch modes of Ga(2)N, with the latter allowed by vibronic coupling to an excited electronic state. The energy of the observed excited neutral state agrees with that calculated for the A (2)Pi(u) state, but the congested nature of this band in the photoelectron spectrum is more consistent with a transition to a bent neutral state.

Spectroscopic Investigation of Al2N and Its Anion via Negative Ion Photoelectron Spectroscopy

“…The appearance of bands X and A is similar to analogous bands seen in the Ga 2 N -PE spectrum. 6 Assignment of these bands is discussed in section IV.…”

“…In this article, we describe the findings for the ground and lowlying electronic states of the Al 2 N molecule using negative ion photoelectron (PE) spectroscopy and compare the results with the isovalent B 2 N and Ga 2 N molecules. 5,6 This investigation represents our continued effort to characterize group III-V molecular clusters [7][8][9][10][11][12][13] by anion PE spectroscopy.…”

Probing chemical dynamics with negative ions

“…This pulsed ion beam instrumentation is based on work by Johnson and Lineberger, 26 with various configurations implemented in our group over the years. [34][35][36][37] Anion PE spectroscopy has been shown to be an extremely versatile technique, since it maps out the electronic and vibrational structures of any neutral species that can be accessed by photodetachment of a negative ion. Somewhat poorer resolution but much higher collection efficiency is achieved using "magnetic bottle" analyzers.…”

Geometrical and electronic properties of GanN2 clusters: A density-functional investigation

“…Himmel and Hebben [4] have performed matrixisolation experiments to study the interaction between Ga atoms and N 2 by using Raman and UV/Vis spectroscopies for detection and analysis. Very recently, Sheehan et al [5] have presented the spectroscopic characterization of the ground and low-lying electronic states of Ga 2 N via anion photoelectron spectroscopy. On the theoretical front, some research works have been reported with particular emphasis on the stoichiometric clusters (Ga n N n , n = 1-12) [6][7][8][9][10][11][12][13][14][15].…”