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Manuscript Title: WVM: a computer program for the determination of lattice parameters and strains in thin films.
Authors: T. Wieder
Program title: WVM
Catalogue identifier: ADDM_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 96(1996)53
Programming language: Fortran.
Computer: IBM RS6000.
Operating system: Unix, AIX, VMS.
Keywords: X-ray diffraction, Lattice parameters, Strain, Thin films, Crystallography.
Classification: 8.

Nature of problem:
Calculate the strain tensor epsilon 2<->and the strain-free lattice parameters of a thin polycrystalline film from measured X-ray reflection positions.

Solution method:
The model of Witt and Vook [1, 2] assumes a biaxial strain state within the film with the restrictions
          epsilon11 = epsilon22 = epsilonb                           (1) 
          epsilon12 = 0                                              (2) 
 
on the strain tensor components and
   
          sigma13 = sigma23 = sigma33 = 0                            (3) 
   
on the stress tensor components. Evaluation of Hooke's law under these assumptions results in a procedure to determine the unstrained lattice parameters a0,1, a0,2, a0,3, alpha0,1, alpha0,2, alpha0,3 [3] and the biaxial strain epsilonb. The model has been extended [4] from the cubic class to any crystal class.

References:
[1] R.W. Vook and F. Witt, Structure and Annealing Behavioiur of Metal Films Deposited on Substrates near 80degrees: I. Copper Films on Glass, J. Appl. Phys. 36 (1965) 49.
[2] F. Witt and R.W. Vook, Thermally Induced Strains in Cubic Metal Films, J. Appl. Phys. 39 (1968) 2773.
[3] T. Wieder, Calculation of thermally induced strains in thin films of any class, J. Appl. Phys. 78 (1995) 838.