Analysis of valence-electron structures of Y/sub 3/Al/sub 5/O/sub 12/(YAG) and Al/sub 2/O/sub 3/, Cr/sub 2/O/sub 2/ (Ruby), a study of certain properties of these laser materials related to their valence-electron structures
A direct method of determination of the valence-electron structure from its crystal structure has been presented by the writer at XIIth International Congress of Crystallography, at Ottawa, 1981. Here the method is applied to determine the valence-electron structures of Y/sub 3/Al/sub 5/O/sub 12/ (YAG) and Al/sub 2/O/sub 3/, Cr/sub 2/O/sub 3/ (ruby) to see how certain properties of these laser materials are related to their valence-electron structures. The first point observed is the very strong, continuous, but zig-zag three-dimensional fractional covalent M-O bond nets (M = Al or Cr) being connected with the high melting points, the great resistance against the puncture by the strong laser beam. In the case of Nd-YAG, the distortion caused by the replacement of the Y atoms by almost the same size Nd atoms is small. On the other hand, because of the similarity of the valence-electron structures of ..cap alpha..-Al/sub 2/O/sub 3/ and Cr/sub 2/O/sub 3/, the replacement of Al atoms by the little larger size Cr atoms in small amount is easily understood. The large atomic spins of magnetic moment m/sub B/ = 2.76 ..mu../sub B/ (= experiment value, the theoretical m/sub B/ = 2.70/sub 2/ ..mu../sub B/) of Cr atoms pointing parallel to the c axis of the hexagonal lattice, is found to be due to the direction of the spin situated in the space of lowest density space of the valence-electron cloud distribution. This agrees with the result of ..cap alpha..-Fe disclosed in the paper Electron theory of the magnetic moment structures of ..cap alpha..-Fe, epsilon-Co, Ni from neutron diffraction experiments presented at the Symposium on Neutron Scattering, Argonne National Laboratory, 1981. This will be found also true in many other oxides like ..cap alpha..-Fe/sub 2/O/sub 3/, FeTiO/sub 3/, MnTiO/sub 3/ and so on.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 5189517
- Report Number(s):
- BNL-31380; CONF-820585-1; ON: DE82016747; TRN: 82-013630
- Resource Relation:
- Conference: Society of Photo-optical Instrumentation Engineers technical symposium, Arlington, VA, USA, 3 May 1982; Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
74 ATOMIC AND MOLECULAR PHYSICS
ALUMINIUM OXIDES
ELECTRONIC STRUCTURE
LASER MATERIALS
NEODYMIUM LASERS
RUBY
RUBY LASERS
YTTRIUM OXIDES
BOND LENGTHS
CHEMICAL BONDS
ELECTRONS
MAGNETIC MOMENTS
VALENCE
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CORUNDUM
DIMENSIONS
ELEMENTARY PARTICLES
FERMIONS
LASERS
LENGTH
LEPTONS
MATERIALS
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SOLID STATE LASERS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
420300* - Engineering- Lasers- (-1989)
640305 - Atomic
Molecular & Chemical Physics- Atomic & Molecular Theory- (-1987)