IMPROVEMENTS ON THE USE OF IMAGE SEEKING FUNCTIONS. Javier Borge, Santiago García-Granda, Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, C/ Julián Clavería, 8, 33006 Oviedo, Spain

Rotation and translation function procedures only reach correct results when powerful mathematical techniques are used to measure the goodness of fit between observed and calculated Patterson maps. Usually, Image Seeking Functions (ISF) [1] solve satisfactorily this problem.

Several tests [2-3] based on computer generated random numbers showed how the behavior of the ISF depends largely on certain relations between statistical descriptors (such as mean and standard deviation) of the Patterson maps.

Real data tests, now performed, confirm the previous results from computer simulation. Useful transformations of observed and calculated data will be suggested to improve the results when applying ISF.

[1] M. J. Buerger. Vector Space and its application in crystal-structure investigation. 1st ed. John Wiley & Sons, Inc. New York. 1959

[2] C. E. Nordman. L.-Y. R. Hsu in Computational Crystallography. (Ed.: D. Sayre). Oxford: Clarendon Press. 1982. pp. 141 -149.

[3] S. García-Granda. J. Borge. A. Gutiérrez-Rodríguez. Anales de Química. Int. Ed. Submitted for publication.