Nonlinear-least-squares analysis of slow motional regime EPR spectra.
A comparison between the full Newton-type optimization NL2SNO, the Levenberg-Marquardt method with the model-trust region modification, and the simplex algorithm is made in the context of the iterative fitting of EPR spectra. EPR lineshape simulations are based on the stochastic Liouville equation (SLE), with an anisotropic diffusion tensor and an anisotropic restraining potential describing the motional amplitude of the spin label. The simplex algorithm was found to be the most reliable, and an approach-incorporating both NL2SNO as well as the downhill simplex methods-is proposed as a strategy-of-choice.
Khairy
Khaled
K
Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA. khairy@mpi-cbg.de
Budil
David
D
Fajer
Piotr
P
D000465:Algorithms; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D016018:Least-Squares Analysis; D008956:Models, Chemical; D008958:Models, Molecular; D017711:Nonlinear Dynamics; D009716:Numerical Analysis, Computer-Assisted