DETERMINATION OF LATTICE PARAMETERS WITH THE AID OF A COMPUTER. Final Report of Metallurgy Program 4.1.8.

The detemnination of precision lattice parameters using a least-squares analytical treatment has been programmed into a computer. Although it was originally coded for the Argonne AVIDAC and GEORGE computers, it is now programmed for the IBM 704. The present program permits the determination of lattice parametsrs and standard errors for the orthorhombic system and for all other crystal systems of higher symmetry. The angular measurements of line positions from a Debye-Scherrer or symmetrical focusing camera or a diffractometer may be given in degrees or radians from several different wavelengths. Provision was made for using aa many as three separate correction terms for eccentricity, absorption, divergence, and others; however, one, two, three, or none at all, may be used. The exact trigonometric function or functions used in these correction terms may be selected from several of those previously suggested. If desired, a weighting factor may also be used for each reflection which may include an observation weight or trigonometric function or both. Examples will be given of lattice parameters obtained for various crystal systems using different correction terms with and without weighting. (auth)