- vpi.lib is the head monomer
- vp1.lib and vp2.lib are the central monomers, differing only for stereochemistry
- vpt_H.lib is the acidic tail monomer
- vpt.lib is the functionalizable acidic tail monomer (for building esters or amides)
Note that standard PVP polymers can be built by using vpi for both the head and tail monomers
I enclose also a pdb file for a 4 monomers PVP as an example of how the polymers could be built. Such parameters were successfully applied for the study of 18 and 40 terms polymers, and are currently being used for further studies on functionalyzed PVP.
Here follows a summary of the Experimental section of the above mentioned article:
Missing parameters for pyrrolidone were derived by HF/6-31G* calculations conduced on atactic, sindiotactic and isotactic polymers consisting of four vinyl pyrrolydone monomers. Final bond length and angle parameters were derived by a least square fitting of all the analogue bonds and angles obtained from the ab-initio geometries. The RED program was used to calculate accurate RESP point charges and a set of two different spatial conformation for each PVP tetramer was used for charge averaging. Parameters were tested by comparing MM results, obtained for a PVP-COOH tetramer (vpi-vp1-vp2-vpt), with ab-initio results.