Hi Joy,
Sorry for the late reply, I only just saw your message.
> On Jun 2, 2016, at 2:51 PM, Jingyi Yan <jyan7.ualberta.ca> wrote:
>
> *> *
> *> Also, I got the error message: fe__k: non-positive Det[1-Wvv*Cvv*Rho]. I
> *
> *> checked the density and the dielectric constant in the input, which are *
> *> fine. I am wondering how should I solve this problem. *
>
I know this isn’t a very helpful error message. What it means is that rism1d can’t calculate the pressure. If you look at the XVV file, you’ll see that your isothermal compressibility is negative.
In my very limited experience with non-polar liquids I’ve found that united atom radii often need to be larger than are typically used in most united atom force fields. Increasing the rmin/2 parameter to 2.4 or higher for the carbons may be suitable. I was able to converge your model with rmin/2=2.4 and xrism but not drism. Since the dielectric constant of octanol is already quite low, xrism may be sufficient. For xrism, this gave an isothermal compressibility of 1.43445968E-003 1/MPa. You’ll have to check the literature to see if this is a reasonable value.
A united atom octanol model was recently used with 1D-RISM
W. Huang, N. Blinov, and A. Kovalenko, J. Phys. Chem. B 119, 5588 (2015).
You may wish to contact the authors for their parameters.
Hope this helps,
Tyler
_______________________________________________
AMBER mailing list
AMBER.ambermd.org
http://lists.ambermd.org/mailman/listinfo/amber
Received on Tue Jun 21 2016 - 11:00:02 PDT
