Thanks for the answer. >You're introducing atomic overlap and thus an energetic singularity from the infinite Coulombic attraction. Is there anything I can do with this?
I posted this question because I'm trying to run a Monte Carlo simulation of a water box but eventually it finds the global energy minimum (-Inf) and can't escape from it. 2013/6/4 Justin Lemkul [via GROMACS] <[email protected] > > > > On 6/3/13 7:49 PM, tnorgd wrote: > > Dear group, > > > > I am not sure how SPC energy actually works - is there really just one > VdW > > interaction - just between two oxygen atoms? > > > > Yep. A lot of force fields work like that. Given the size of H atoms > relative > to their heavy atom counterparts, the heavy atom to which they are > connected > generally governs the vdW interactions. > > > If so, when I place a hydrogen atom of one water molecule at the > location of > > the oxygen from another water, > > the two oxygens are separated by the distance of H-O bond length i.e. > 1.0A. > > The only VdW interaction is repulsive but finite (and equal ~4E6) but > the > > electrostatic between H and O is -Inf = 1/0.0 > > > > What's wrong? > > > > Nothing. That makes perfect sense. You're introducing atomic overlap and > thus > an energetic singularity from the infinite Coulombic attraction. > > -Justin > > -- > ======================================== > > Justin A. Lemkul, Ph.D. > Research Scientist > 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 [hidden > email]<http://user/SendEmail.jtp?type=node&node=5008760&i=0> > 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 [hidden > email]<http://user/SendEmail.jtp?type=node&node=5008760&i=1>. > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > > ------------------------------ > If you reply to this email, your message will be added to the discussion > below: > > http://gromacs.5086.x6.nabble.com/Specific-question-regarding-SPC-water-model-tp5008757p5008760.html > To unsubscribe from Specific question regarding SPC water model, click > here<http://gromacs.5086.x6.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=5008757&code=dG5vcmdkQGdtYWlsLmNvbXw1MDA4NzU3fC0xODM5OTYzNjc=> > . > NAML<http://gromacs.5086.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml> > -- gmx-users mailing list [email protected] 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 [email protected]. * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
