Two‐photon absorption of F‐centres in KCl

Abstract

Picosecond light pulses are used to give evidence of the occurrence of two-photon absorption of F-centres in KCl. The results, especially the unchanged fluorescence decay, are discussed on the basis of the mixed-state model of P-centres.Unter Verwendung von Pikosekunden-Impulsen wird das Auftreten einer Zwei-Photonen-Absorption durch F-Zentren in KCI nachgewiesen. Diese Ergebnisse, insbesondere das unveranderte Fluoreszenzabklingen, werden auf der Basis des F-Zentren-Modells gemischter Zustande diskutiert.

Dynamics of nuclear wave packets at theFcenter in alkali halides

“…The fact that the 2s state lies higher than the 2p state in the FCS but is lower in the RES indicates that the 2s and 2p levels cross between the two states, so that a dynamic nonradiative transition is expected to occur. In order to detect the presence of the 2s-2p level crossing, resonant secondary radiation (RSR) spectra have been measured under the conditions of one-photon excitation (1s-2p transition) [45][46][47][48][49][50][51][52][53] and twophoton excitation (1s-2s transition) [88][89][90][91], and numerical calculations based on the RSR theory have been done [92,93]. (A framework of the RSR theory is described in appendix A.)…”