Dear Sir, I would like to know if the MCDHO water potential mentioned in the paper J. Chem. Phys., 116(22) 9602-9610, 2002 (Hess, Saint-Martin & Berendsen) is available in Gromacs. Best regards, -- Dr. Rafael R. Pappalardo Dept. Química Física, Fac. de Química, Univ. de Sevilla (Spain) e-mail: rafapa at catedrax.us.es