Dear gmx users, I am thankful to Dr.Mark and Dr.Osmair for their responce to my queries. As per their suggestion, I checked ions.itp file in that sodium atoms are represented by NA+ in opls force field. I am using gromacs 3.3.1 version.
[moleculetype ] ; molname nrexcl NA+ 1 [ atoms ] ; id at type res nr residu name at name cg nr charge mass 1 opls_407 1 NA+ NA 1 1 22.98977 As per Dr.Osmair suggestion, I built a sodium.itp file, the file was shown below. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ [ moleculetype ] ; NAme nrexcl NA+ 1 [ atoms ] ; nr type resnr residue atom cgnr charge mass typeB chargeB massB 1 opls_407 1 NA+ NA 1 1 22.9898 ; qtot 1 2 opls_407 2 NA+ NA 2 1 22.9898 ; qtot 2 3 opls_407 3 NA+ NA 3 1 22.9898 ; qtot 3 4 opls_407 4 NA+ NA 4 1 22.9898 ; qtot 4 5 opls_407 5 NA+ NA 5 1 22.9898 ; qtot 5 6 opls_407 6 NA+ NA 6 1 22.9898 ; qtot 6 7 opls_407 7 NA+ NA 7 1 22.9898 ; qtot 7 8 opls_407 8 NA+ NA 8 1 22.9898 ; qtot 8 9 opls_407 9 NA+ NA 9 1 22.9898 ; qtot 9 10 opls_407 10 NA+ NA 10 1 22.9898 ; qtot 10 11 opls_407 11 NA+ NA 11 1 22.9898 ; qtot 11 12 opls_407 12 NA+ NA 12 1 22.9898 ; qtot 12 ......... .......... .......... and also tried with the fallowing type... [ moleculetype ] ; Name nrexcl Sodium 1 [ atoms ] ; nr type resnr residue atom cgnr charge mass typeB chargeB massB 1 opls_405 1 Na Na 1 1 35.4530 ; qtot 1 2 opls_405 2 Na Na 2 1 35.4530 ; qtot 2 3 opls_405 3 Na Na 3 1 35.4530 ; qtot 3 4 opls_405 4 Na Na 4 1 35.4530 ; qtot 4 5 opls_405 5 Na Na 5 1 35.4530 ; qtot 5 6 opls_405 6 Na Na 6 1 35.4530 ; qtot 6 7 opls_405 7 Na Na 7 1 35.4530 ; qtot 7 8 opls_405 8 Na Na 8 1 35.4530 ; qtot 8 9 opls_405 9 Na Na 9 1 35.4530 ; qtot 9 ............. ............. ............. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ When i run grompp command to prepare bilater-ions.tpr file, I couldn't observe any error message and shown below. xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx processing topology... Generated 345696 of the 345696 non-bonded parameter combinations Generating 1-4 interactions: fudge = 0.5 Generated 345606 of the 345696 1-4 parameter combinations Excluding 3 bonded neighbours for POPE 96 turning all bonds into constraints... Excluding 3 bonded neighbours for DPOP 32 turning all bonds into constraints... Excluding 2 bonded neighbours for SOL 3909 turning all bonds into constraints... Excluding 1 bonded neighbours for NA+ 1 turning all bonds into constraints... processing coordinates... double-checking input for internal consistency... Velocities were taken from a Maxwell distribution at 303 K renumbering atomtypes... converting bonded parameters... # ANGLES: 7520 # PDIHS: 3424 # RBDIHS: 2944 # IDIHS: 544 # LJ14: 3680 # CONSTR: 6560 # SETTLE: 3909 Walking down the molecule graph to make shake-blocks initialising group options... processing index file... Making dummy/rest group for Acceleration containing 18447 elements Making dummy/rest group for Freeze containing 18447 elements Making dummy/rest group for Energy Mon. containing 18447 elements Making dummy/rest group for VCM containing 18447 elements Number of degrees of freedom in T-Coupling group POP is 10079.18 Number of degrees of freedom in T-Coupling group DPO is 3423.72 Number of degrees of freedom in T-Coupling group SOL is 23452.10 Number of degrees of freedom in T-Coupling group NA+ is 95.99 Making dummy/rest group for User1 containing 18447 elements Making dummy/rest group for User2 containing 18447 elements Making dummy/rest group for XTC containing 18447 elements Making dummy/rest group for Or. Res. Fit containing 18447 elements Making dummy/rest group for QMMM containing 18447 elements T-Coupling has 4 element(s): POP DPO SOL NA+ Energy Mon. has 1 element(s): rest Acceleration has 1 element(s): rest Freeze has 1 element(s): rest User1 has 1 element(s): rest User2 has 1 element(s): rest VCM has 1 element(s): rest XTC has 1 element(s): rest Or. Res. Fit has 1 element(s): rest QMMM has 1 element(s): rest Checking consistency between energy and charge groups... Calculating fourier grid dimensions for X Y Z Using a fourier grid of 65x65x70, spacing 0.119 0.119 0.117 writing run input file... xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx When I am runing mdrun command, I got the fallowing error messages and after some time segmentation fault. zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Step 32, time 0.064 (ps) LINCS WARNING relative constraint deviation after LINCS: max 0.002582 (between atoms 5262 and 5310) rms 0.000038 bonds that rotated more than 30 degrees: atom 1 atom 2 angle previous, current, constraint length 5262 5310 31.2 0.1000 0.0997 0.1000 Step 33, time 0.066 (ps) LINCS WARNING relative constraint deviation after LINCS: max 0.003343 (between atoms 5262 and 5310) rms 0.000057 bonds that rotated more than 30 degrees: atom 1 atom 2 angle previous, current, constraint length 5368 5416 69.4 0.0999 0.1001 0.1000 Step 34, time 0.068 (ps) LINCS WARNING relative constraint deviation after LINCS: max 0.005428 (between atoms 5262 and 5310) rms 0.000076 bonds that rotated more than 30 degrees: atom 1 atom 2 angle previous, current, constraint length 5262 5310 67.9 0.1003 0.0995 0.1000 5368 5416 47.0 0.1001 0.1002 0.1000 Step 35, time 0.07 (ps) LINCS WARNING relative constraint deviation after LINCS: max 0.002371 (between atoms 5368 and 5416) rms 0.000036 bonds that rotated more than 30 degrees: atom 1 atom 2 angle previous, current, constraint length 5262 5310 43.4 0.0995 0.1002 0.1000 5368 5416 40.9 0.1002 0.0998 0.1000 zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Can you tell where I have done mistake. Any suggestion is appreciated. Thank you in advance. with best regards, Nagaraju ____________________________________________________________________________________ Luggage? GPS? Comic books? Check out fitting gifts for grads at Yahoo! Search http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz _______________________________________________ gmx-users mailing list gmx-users@gromacs.org http://www.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to [EMAIL PROTECTED] Can't post? Read http://www.gromacs.org/mailing_lists/users.php