Field PCFF not found

Hi,

I’m new to EMC and trying to run a script from a previous post (Polymer with straight backbone - #4 by veld):

ITEM OPTIONS

replace true
field pcff
density 0.01
temperature 1
number true
focus true

ITEM END

ITEM GROUPS

ethyl CC, 1,ethyl:2
methyl *C, 1,ethyl:1, 1,ethyl:2

ITEM END

ITEM CLUSTERS

poly alternate, 1

ITEM END

ITEM POLYMERS

poly
100 ethyl, 10, methyl, 2

ITEM END

After I run ‘emc_setup.pl polymer’, it gives one warning:‘field ‘pcff’ not found; no changes’ and opls-ua is used. I am wondering how I can correctly apply the PCFF force field to build a polymer.

Thanks in advance for your help!

Hi,

The easiest way to fix this problem is to set the environment variable EMC_ROOT. When you are using LINUX, you can set this variable by

export EMC_ROOT=/your/emc/version

You can make this your default by permanently adding the above to your ~/.bashrc. See ‘How to setup EMC for Windows’ for setting environment variables under Windows.

Thanks for the reply! Actually I have already set the environment variables according to the link you posted (please see screenshots below) before I tried running the script.


image