<font class="Apple-style-span" size="3">Dear All,</font>
<div><font class="Apple-style-span" size="3"><br></font></div><div><font class="Apple-style-span" size="3">I have a simulation set up for a mixture of carbon dioxide and water system which runs perfectly on Gromacs 4.0.5 version. I have run these simulations at different temperatures and pressures, from the same starting configuration and the simulation proceeds smoothly in the 4.0.5 version. However, when I use exactly the same files to run the simulation in 4.5.4 version, the system crashes and writes out several pdb files. I was wondering if there is anything specific that has been changed between the two versions. I have pasted the mdp file of the simulations below. Any input will be much appreciated.</font></div>
<div><font class="Apple-style-span" size="3"><br></font></div><div><font class="Apple-style-span" size="3">MDP File </font></div><div><font class="Apple-style-span" size="3"><br></font></div><div><font class="Apple-style-span" size="3"><div>
title = 100% occupancy CO2 hydrate ; a string</div><div>cpp = /lib/cpp ; c-preprocessor</div><div>dt = 0.002 ; time step</div><div>nsteps = 15000000 ; number of steps</div>
<div>nstcomm = 10 ; reset c.o.m. motion</div><div>nstxout = 0000 ; write coords</div><div>nstvout = 0000 ; write velocities</div><div>
nstlog = 25000 ; print to logfile</div>
<div>nstenergy = 500 ; print energies</div><div>xtc_grps = OW_HW1_HW2_CO2 </div><div>nstxtcout = 1000</div><div>nstlist = 10 ; update pairlist</div>
<div>ns_type = grid ; pairlist method</div><div>coulombtype = PME</div><div>rvdw = 1.2 ; cut-off for vdw</div><div>rcoulomb = 1.2 ; cut-off for coulomb</div>
<div>rlist = 1.2 ; cut-off for coulomb</div><div>DispCorr = EnerPres</div><div>Tcoupl = Nose-Hoover</div><div>ref_t = 270 </div><div>tc-grps = System</div>
<div>tau_t = 0.5 </div><div>Pcoupl = Parrinello-Rahman</div><div>Pcoupltype = semiisotropic ; pressure geometry</div><div>tau_p = 1.0 1.0 ; p-coupoling time</div>
<div>compressibility = 4.5e-5 4.5e-5 ; compressibility</div><div>ref_p = 30.5 30.5 ; ref pressure</div><div>gen_vel = yes ; generate initial vel</div>
<div>gen_temp = 260 ; initial temperature</div><div>gen_seed = 372340 ; random seed</div><div>constraint_algorithm = shake</div><div>constraints = all-bonds </div>
<div><br></div></font></div><div><font class="Apple-style-span" size="3">-------</font></div><div><font class="Apple-style-span" size="3"><br></font></div><div><font class="Apple-style-span" size="3"><br></font></div><div>
<font class="Apple-style-span" size="3">Thank you,</font></div><div><font class="Apple-style-span" size="3"><br></font></div><div><font class="Apple-style-span" size="3">Sincerely,</font></div><div><font class="Apple-style-span" size="3">Sapna</font></div>