DEPARTMENT OF MATHEMATICAL SCIENCES

APPLIED AND COMPUTATIONAL MATHEMATICS SEMINAR

**Speaker:**Anton Gagin, National Institute of Standards and Technology

**Title: ***
Accounting for Unknown Systematic Errors in Crystal Structure Refinements: A Bayesian Statistics Approach
*

**Abstract:**
Determination of crystal structures using X-ray/neutron powder diffraction is an inverse problem of finding a disposition of atoms by fitting an experimental diffraction pattern with a model signal. The accuracy of the obtained structural parameters is often limited by systematic errors that affect intensities and shapes of diffraction peaks. We developed a probabilistic method that accounts for systematic errors using Bayesian statistics and marginalization of error corrections, without assuming any particular model for these errors. We will demonstrate the advantages of our method using an example of structural refinements that employ simultaneous fitting of X-ray and neutron diffraction data.

**Time:** Friday, February 20, 2015, 1:30-2:30 p.m.

**Place:** Exploratory Hall, Room 4106

Department of Mathematical Sciences

George Mason University

4400 University Drive, MS 3F2

Fairfax, VA 22030-4444

http://math.gmu.edu/

Tel. 703-993-1460, Fax. 703-993-1491