Seminar Announcement

Large-scale Normal Coordinate Analysis for Molecular Vibration

Chao Yang
Computer Science & Mathematics Division
Oak Ridge National Laboratory

Friday, January 7, 2000
Bldg. 921, Room 137
10:00 a.m. - 11:00 a.m.

Normal Coordinate Analysis (NCA) is an important tool for studying vibrational features of molecular structures at the atomic level. To perform NCA, one must calculate second derivatives of the potential function with respect to the Cartesian coordinates. This yields a so-called force constant matrix which is often sparse. The eigenvalues and eigenvectors of this matrix characterize the vibrational frequencies and displacement patterns of each atom. Currently, the use of NCA has been limited to relatively small systems. This is partly due to the lack of efficient numerical algorithms for large-scale NCA calculation. In this talk, several techniques for improving the computational efficiency of large-scale NCA will be presented. In particular, we will examine a special Hessian calculation technique that reduces the amount work by utilizing a set of internal coordinates as intermediate variables. Various strategies for accelerating the eigenvalue calculation will also be discussed.

This is joint work with Don Noid and Bobby Sumpter at ORNL Chemical and Analytical Sciences Division.

This seminar is hosted by the Computational Sciences and Mathematics Research Department at Sandia National Labs in Livermore, CA. For more information on this or other events, visit http://csmr.ca.sandia.gov/news.html. Visitors from outside Sandia require advance arrangements in order to attend. For more information, please contact the CSMR office management assistant Doretha Smith at dahall@sandia.gov or (925) 294-4630.