I would like to simulate a copolymer with 25 units of PE and 25 units of PEG in MS. During this task I was troubled with an convergence issue regarding the mesocite geometry optimization. Hence I need some advice in order to solve this problem for a further DPD calculation.

For this reason I tried to write down all the steps that a have been working on until this issue (pls see the attached MS-file):

1.) Define a copolymere with an ethylene and ethylenglycol repeating unit

2.) Perform a forcite geometry optimization

3.) Define the coarse grain under mesostructure as well as the bead type (see file)

4.) Calculate the repulsions parameter a = 104 + 3.5 X between PE and PEG

(while X represents the Flory-Huggins interaction parameter which I calculated beforehand)

5.) Define a DPD forcefield where you enter the repulsions parameter in a table

(a = 104 for same block interaction like PE/PE and PEG/PEG and a = 195 for different block interaction like PE/PEG)

6.) Define a mesostructure template (120•120•120 A)

7.) Fill the template with the .xcd-files from the copolymers

8.) add the forcefield to the file

9.) run the geometry optimization (COVERGENCE FAILURE)

...

10.) Perform the DPD calculation (intented GOAL)

Link to google drive file (because the zip file wont upload for some reason):

https://drive.google.com/drive/folders/1yFiXYGp7PJd6xKtpDHp9QGnsiqLZMy01?usp=sharing