The apparent detachment energy at the <sup>3</sup>P<sub>2</sub> threshold, for mean photoelectron kinetic energies ranging from 33.8 to 70.7 m<sup>−1</sup>

2013-06-10T00:00:00Z (GMT) by M Vandevraye C Drag C Blondel
<p><strong>Figure 3.</strong> The apparent detachment energy at the <sup>3</sup>P<sub>2</sub> threshold, for mean photoelectron kinetic energies ranging from 33.8 to 70.7 m<sup>−1</sup>. Open circles, triangles and diamonds are data taken at 183, 267 and 364 V m<sup>−1</sup>, respectively. Extrapolation down to = 0 produces a measurement of the <sup>3</sup>P<sub>2</sub> PT, 1239 711.8(11) m<sup>−1</sup>. The continuous line is the linear regression of the data, the nearly zero slope of which reveals that the error on the electric field value was probably lower than 0.5%. Larger error bars for lower electric fields are due to the larger perturbation of electron interferograms by spurious electric fields in the vicinity of the electron detector.</p> <p><strong>Abstract</strong></p> <p>A beam of Sn<sup>−</sup> ions produced by a caesium sputtering ion source is photodetached in the presence of an electric field, with a single-mode ring Ti:Sa laser. The laser wavelength, about 806 nm, is set just above the excitation threshold of the <sup>3</sup>P<sub>2</sub>, highest fine-structure sublevel of the <sup>3</sup>P ground-term of Sn I. The photoelectron energy is measured by photodetachment microscopy. The measured photodetachment threshold is 1239 711.8 (11) m<sup>−1</sup>, from which an improved value of the electron affinity of tin can be deduced: 896 944.7 (13) m<sup>−1</sup> or 1.112 070 (2) eV.</p>