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From: Tyler Luchko (Lists) <"Tyler>

Date: Wed, 20 Jul 2016 16:28:46 -0700

Hi Shijie,

While DRISM was originally derived as a bridge correction, it is effectively treated as a separate integral equation. From the point of view of calculating a solution, we have the DRISM integral equation coupled with a closure such as HNC or KH. The bridge function output is for the closure in this context.

rism1d does calculate the \tilde\chi term (zkvv in the code) but does not attempt to calculate the effective bridge correction in Eq. 28 to which you refer. It may (should?) be possible to calculate the effective bridge correction but the current code does not do this and I have never tried.

Tyler

*> On Jul 20, 2016, at 4:01 PM, Shijie Sheng <sshen004.ucr.edu> wrote:
*

*>
*

*> Hi Tyler,
*

*>
*

*> I appreciate your clarification on the dielectric asymptotic
*

*> parameter.
*

*> But for DRISM, isn't the bridge function calculated through the
*

*> chain sum definition of \chi according to Eq.(28) of Perkyns and
*

*> Pettitt (JCP,97:7656)?
*

*> If it is, then it should be the same for whatever the closure you choose.
*

*>
*

*> On Wed, Jul 20, 2016 at 10:48 AM, Tyler Luchko (Lists) <
*

*> tluchko.lists.gmail.com> wrote:
*

*>
*

*>>
*

*>>> On Jul 19, 2016, at 11:14 PM, Shijie Sheng <sshen004.ucr.edu> wrote:
*

*>>>
*

*>>> Hi,
*

*>>>
*

*>>> I carefully checked the code of rism1d and the existing literature
*

*>>> about the dielectric constant relation to correlation functions, and
*

*>> found
*

*>>> an inconsistency in hc(k).
*

*>>> According to the code (line 397 to line 407 of
*

*>>> rism1d_potential_c.F90) based on the seminal article of Perkyns and
*

*>> Pettitt
*

*>>> (JCP,97:7656), the hc(k) is calculated through Eq.(34) from that article.
*

*>>> My question is that if the equation still holds true for mixtures. I ask
*

*>>> this question because hc(k) is interpreted differently in Eq.(9)~(12) of
*

*>>> Kvamme's article (Interaction-site Representation of polar mixtures and
*

*>>> electrolyte solutions). I was wondering which one is correct for
*

*>>> *mixtures. *
*

*>>
*

*>> I recommend looking at
*

*>> B. Kvamme, Phys. Chem. Chem. Phys. 4, 942 (2002)
*

*>> Eq. 5 and
*

*>> M. Holovko, A. Kovalenko, and F. Hirata, Journal of Molecular Liquids 217,
*

*>> 103 (2016)
*

*>> between Eq. 10 and 11, where the notation is a little clearer, IMO. This
*

*>> is what is implemented in the lines you cite and is Kvamme’s extension of
*

*>> DRISM to mixtures.
*

*>>
*

*>>> * Plus, *the bridge output in rism1d is not reasonable to me. For
*

*>>> example, when one uses DRISM/HNC, none zero bridge functions should be
*

*>>> obtained. The HNC closure is in the sense of C_H\equivC-b not the direct
*

*>>> correlation function C. However, the bridge term is set to zero in
*

*>>> rism1d_hnc_c.F90.
*

*>>
*

*>> I’m not sure what you mean here. The general closure equation is given by
*

*>>
*

*>> g(r) = exp[ -\beta u(r) + h(r) - c(r) + b(r)]
*

*>>
*

*>> where b(r) is the bridge function. In HNC b(r) = 0.
*

*>>
*

*>> I hope this helps,
*

*>>
*

*>> Tyler
*

*>> _______________________________________________
*

*>> AMBER mailing list
*

*>> AMBER.ambermd.org
*

*>> http://lists.ambermd.org/mailman/listinfo/amber
*

*>>
*

*>
*

*>
*

*>
*

*> --
*

*> Best regards,
*

*> ------------------------
*

*> Shijie Sheng
*

*> UCR CEE Department
*

*> _______________________________________________
*

*> AMBER mailing list
*

*> AMBER.ambermd.org
*

*> http://lists.ambermd.org/mailman/listinfo/amber
*

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Received on Wed Jul 20 2016 - 16:30:02 PDT

Date: Wed, 20 Jul 2016 16:28:46 -0700

Hi Shijie,

While DRISM was originally derived as a bridge correction, it is effectively treated as a separate integral equation. From the point of view of calculating a solution, we have the DRISM integral equation coupled with a closure such as HNC or KH. The bridge function output is for the closure in this context.

rism1d does calculate the \tilde\chi term (zkvv in the code) but does not attempt to calculate the effective bridge correction in Eq. 28 to which you refer. It may (should?) be possible to calculate the effective bridge correction but the current code does not do this and I have never tried.

Tyler

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Received on Wed Jul 20 2016 - 16:30:02 PDT

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