Hi Christopher
There were a couple recent posts on this topic (see below).
I assume you have separate DATA files for each system you want to combine.
In addition to manually using a text-editor, as Ray suggested, there are several tools to merge multiple data files together:
-
read_data (the lammps input-script command):
http://sourceforge.net/p/lammps/mailman/message/34481431/ -
pizza.py (a python module):
http://lammps.sandia.gov/threads/msg11838.html -
topotools (included with VMD):
https://sites.google.com/site/akohlmey/software/topotools/topotools-tutorial—various-tips-tricks#TOC-Combine-multiple-data-files-with-overlap-detection-and-removal -
moltemplate.sh (a stand-alone program):
http://lammps.sandia.gov/threads/msg55306.html
http://sourceforge.net/p/lammps/mailman/message/34482391/
http://lammps.sandia.gov/threads/msg41643.html
Moltemplate allows you to turn each DATA file into a “molecule-object”. These objects include coordinates, charges, masses, bonds, angles, dihedrals, impropers, constraints, groups, and force-field information for each system. You can manually move and rotate these objects, duplicate them, and combine them together, and even delete individual atoms (to prevent atom overlap, for example). However moltemplate does not currently detect atom-overlap and remove solvent molecules automatically. (Topotool can.) If you decide to use moltemplate, be sure to download the latest version at www.moltemplate.org. (Incidentally, there were some relevant bugs fixed on 2015-9-22)
Cheers
Andrew