If you do not find the parameters for vanadium, you could try to develop

them using experimental physical chemistry properties of the ion and MD

simulations.

In the following reference you can find a suitable method to develop

them that worked for me in the development of Pb and Cd ion parameters:

Alexandre S. de Araujo,*,† Milton T. Sonoda,† Oscar E. Piro,‡ and

Eduardo E. Castellano, "Development of New Cd2+ and Pb2+ Lennard-Jones

Parameters for Liquid Simulations", J. Phys. Chem. B 2007, 111, 2219-2224

I also manually done one topology file! I also attached the file.

Cheers

Thanks Mr. Razzokov

for your help. i will try to use your file as well as trying to build a topology file.