Title:  		LATTPARM   
KeyWords:  		Powder Diffraction, Lattice Parameters
Computer:        	PC, XT, AT
Operating System:     	MS(PC)-DOS
Programming Language:  	TURBO Pascal
Hardware:              	Math Co-Processor desirable
Author:                  Roy Garvey
Correspondence Address:  Department of Chemistry
                         North Dakota State University
                         Fargo, North Dakota
                         58105 - 5516     U S A

      Using the algorithm of Visser (1969), the problem of finding the
lattice parameters from powder diffraction data becomes one of finding the
six constants, A, B, C, D, E, and F where
Q(hkl)  =  10**4 / d**2  =  hh A + kk B + ll C + kl D + hl D + hk F       < 3 >
The unknown unit cell so derived will be triclinic.
      A perfectly general approach to the problem is to first find zones of
the lattice (net-planes of the reciprocal lattice containing the origin).
Any two such zones will have a line of intersection.  If the angle between
two such zones is found, a reciprocal lattice is determined.  Sometimes this
lattice can be reduced (described on symmetry axes in the reciprocal lattice).
---------------------------------------------------------------------------