Accession Number : ADA302772

Title :   The Role of Valence-Band Excitation in Laser Ablation of KCl.

Descriptive Note : Rept. for 1 Feb 87-31 Jan 91,

Corporate Author : VANDERBILT UNIV NASHVILLE TN

Personal Author(s) : Haglund, Richard F., Jr. ; Tang, Kai ; Bunton, Patrick H. ; Wang, Ling-Jun

PDF Url : ADA302772

Report Date : OCT 1990

Pagination or Media Count : 14

Abstract : We present recent measurements of excited-atom and ion emission from KCl surfaces illuminated by vacuum-ultraviolet synchrotron radiation (hv = 8-28 eV) and ultraviolet laser light (hv = 4 eV). At low intensities characteristic of the synchrotron experiments, excited atoms are desorbed by simple valence-band excitation process involving the metallization of the KCl surface. At the higher intensities typical of laser desorption and ablation, we observe a strong decrease in K emission as a function of the number of laser shots, but an essentially constant yield of Cl*. K+ and Cl- emission at high intensities show similar behavior. The energetics of these desorption phenomena can be treated in a bond-orbital model which shows that creation of a single valence hole is sufficient to excite an ion to an anti-bonding state. jg p3

Descriptors :   *ABLATION, *EXCITATION, *LASERS, *VALENCE BANDS, *POTASSIUM CHLORIDE, EMISSION, IONS, REPRINTS, HIGH RATE, ULTRAVIOLET RADIATION, DAMAGE, RESISTANCE, INTENSITY, VACUUM, OPTICAL MATERIALS, ATOMS, ATOMIC ORBITALS, CHEMICAL BONDS, ENERGETIC PROPERTIES, DESORPTION, ULTRAVIOLET LASERS, LOW INTENSITY, SYNCHROTRONS, METALLIZING.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Lasers and Masers
      Atomic and Molecular Physics and Spectroscopy
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE