CN B --> X emission in electron-stimulated desorption from alkali halides: Population analysis via nonlinear models
Abstract
Excitation of crystalline KBr, KCl, and LiF with electrons of energy 60-1000 eV produces weak emission in the 360-420 nm region, identified as the B→ X electronic transition in the CN radical. The emission is attributed to CN molecules that leave the surface of the crystal in their electronically excited B 2Σ+ state. The resulting spectra, which are rotationally unresolved, are analyzed by novel nonlinear fitting procedures to yield information about the vibrational and rotational population distributions. For CN(B) produced via electron-stimulated desorption from LiF, the vibrational populations approximate a temperature of 1500 K, while the rotational abundances can be represented as a sum of two Boltzmann distributions having temperatures of 660 K (81%) and 90 K (19%). For ESD from KBr, the rotational distribution is adequately represented as a single Boltzmann at ∼ 590 K.
- Publication:
-
Journal of Chemical Physics
- Pub Date:
- October 1990
- DOI:
- 10.1063/1.459647
- Bibcode:
- 1990JChPh..93.5281X
- Keywords:
-
- Alkali Halides;
- Cyanogen;
- Desorption;
- Electron Impact;
- Emission Spectra;
- Nonlinear Systems;
- Radicals;
- Crystals;
- Electron Beams;
- Electron Transitions;
- Lithium Fluorides;
- Potassium Bromides;
- Potassium Chlorides;
- Visible Spectrum;
- Atomic and Molecular Physics