Iodine molecule covalente excited states as determined by threshold electron spectrometry

Abstract

The iodine molecule has been investigated by a threshold electron spectrometer in the incident electron energy range from 1.00 eV to 3.5eV. From the threshold electron spectrum contributions for excitation of three states known from optical spectrometry have been subtracted. The remaining signal has been interpreted by four curves similar in shape to those in absorption optical spectroscopy into antibonding energy states. The detected maxima have been attributed to the following valence excited states of the iodine molecule: 3П2u(2u), 3П0u-(0u-), 3П2g(2g), and 3П1g(1g), respectively. With the knowledge of the energy ranges within which the signal from a particular state appears, the predicted values of equilibrium distances of iodine atom nuclei and estimated values of vibrational transition frequency potential energy curves have been constructed, too.

Keywords

• electron impact
• iodine molecule
• excitation
• valence states