EMISSION OF NA ATOMS FROM UNDAMAGED AND SLIGHTLY DAMAGED NACL (100) SURFACES BY ELECTRONIC EXCITATION

We have carried out high-sensitivity measurements of the emission of N a atoms induced by irradiation with mus electron pulses of unirradiate d NaCl (100) surfaces and with ns laser pulses of the NaCl (100) surfa ces preirradiated with electrons. Similar to the results of ion bombar dment, irradiation with an electron pulse is found to cause spontaneou s emission of Na atoms with observable delays below 100-degrees-C. It is found also that irradiation with a ns laser pulse of the preirradia ted surface causes emission of Na atoms. The excitation spectrum for t he laser-induced emission shows a peak near the F-band maximum. The yi elds of both the initial electron-pulse-induced emission and laser-ind uced emission on preirradiated surface are found to be reduced as the surface is damaged.