Thanks Justin. I am using flexibale water model for my system. I am refering a paper J. Chem. Phys. 124, 024503 (2006). Author have used Amber type force field.
i.e. 1/2 Kbond (r-req)**2 + 1/2 Kangle(theta-thetaeq)**2. Kbond = 443153.3808 kJ/mol nm**2 Kangle= 317.5656 kJ/mol rad**2. I am using olss-aa force field parameters in Gromacs VERSION 4.0.7. I checked some papers in which author have used opls aa force field. 1/2 factor is not in opls force field IF I compare opls and amber. My question is in .itp file should I use Kbond and Kangle as it is or should I consider the 1/2 factor then I use them. Thanks Nilesh On Fri, May 6, 2011 6:36 pm, Justin A. Lemkul wrote: > > > Nilesh Dhumal wrote: > >> Hello, >> >> >> How can I convert ambar force field to opls force field. >> >> >> Should I half the force constant of bond (Ka) and angle (Kb)? >> >> > > Why would you do that? Most of the bonded parameters in OPLS were taken > from AMBER directly, IIRC. If you need to parameterize some new bonded > parameters, you'd be better served deriving them in a way that is > compatible with the modern OPLS-AA force field (probably QM/geometry > optimization), rather than trying to hack something together. > > -Justin > > > -- > ======================================== > > > Justin A. Lemkul > Ph.D. Candidate > ICTAS Doctoral Scholar > MILES-IGERT Trainee > Department of Biochemistry > Virginia Tech > Blacksburg, VA > jalemkul[at]vt.edu | (540) 231-9080 > http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin > > > ======================================== > -- > gmx-users mailing list gmx-users@gromacs.org > http://lists.gromacs.org/mailman/listinfo/gmx-users > Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/Search before posting! > Please don't post (un)subscribe requests to the list. Use the > www interface or send it to gmx-users-requ...@gromacs.org. Can't post? Read > http://www.gromacs.org/Support/Mailing_Lists > > > -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
