CCL: BFGS method

["Mahmoud A. A. Ibrahim" <m.ibrahim]-[compchem.net>]

 Sent to CCL by: "Mahmoud A. A. Ibrahim" [m.ibrahim.:.compchem.net]
 Dear Basma
 BFGS (Broyden-Fletcher-Goldfarb-Shanno) is a pseudo Newton-Raphson
 Algorithm used to update Hassian matrix during geometry optimization.
 This method uses second derivate of energy to find the local minima,
 rather than Steepest and conjugate gradient methods which use first
 derivate of energy.
 SP4 (and SP5) is AMMP force filed, in which the force constants are
 calculated, not recalled from parameter files (bond length, bond angle
 and torsion angle files), and it's called atom oriented force filed.
 MM,Tripos,MMFF,AMBER,CHARMm,..etc are different force field
 parameterized against different molecules set and using different
 force field equations. Each one of these force fields is dominate for
 its parameterized set, for example, AMBER is working well for
 biological systems, MMFF is working well for the organic compounds.
 These force fields recall the force constant from parameters files
 (NOT compute it).
 Sincerely;
 M. Ibrahim
 On 2/3/10, Basma Ghazal basmaghazal .. ymail.com
 <owner-chemistry{:}ccl.net> wrote:
 >
 >
 >
 >
 >
 > Dear CClers:
 >
 > I want to begin my work on docking by redoing a previous work. That uses
 > BFGS method for the minimization of the compounds.
 >
 > I want to know what is the different between these method and SP4, TRIPOS,
 > MMFF94x and the other methods.
 >
 > I will be highly appreciated if any one explains this to me.
 >
 > Best Regards,
 >  ________________________________
 >
 >
 > Basma S. Ghazal
 > MSc. organic Chemistry
 >
 > “Drug design"
 >
 >  Egypt.
 >
 >
 >
 --
                   Mahmoud A. A. Ibrahim
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