up SearchFeedback[help] CPMCnet   The program r2r1_diffusion
uses the approach of Tjandra, et al. [J. Am. Chem. Soc.
117:12562-12566 (1995)] to determine the diffusion tensors for
spherical, and axially-symmetric motional models from
experimental nitrogen-15 spin relaxation data. Analysis of a
fully anisotropic diffusion tensor has not yet been implemented.
The program quadric_diffusion can be used to evaluate an
anisotropic diffusion tensor in the limit of small anisotropy.
Usage: r2r1_diffusion control_file The control_file contains the
following information: #_of_entries (in the r2r1_file)
spectrometer_field (MHz) #_of_simulations D_isotropic Dpar/Dper
theta phi axial_ratio_low axial_ratio_high #steps
output_pdb_file_name (for axially symmetric model) D_isotropic,
Dpar/Dper, theta and phi are initial estimates of the elements
and orientations of the diffusion tensor. D_isotropic is the
only required entry; Dpar/Dper, theta and phi can be set to
1.00, 0.0, and 0.0 respectively. Ratio_hi and Ratio_low set l