<div dir="ltr"><p>Dear users!<br></p><p>I'm trying to make forcefield oplsaa for fullerene. I already have modified files (see it in the end of the letter), but i have a problem with torsion parameters - torsion angles are different, but atom type is the same - alkene. Length and angles were taken as an average. After pdb2gmx i have normal .gro and .top file (but with wrong parameters for torsions). during the minimization my system blows. </p>
<p>Could anyone give any clue about my problem? May be somebody already has right topology file for my fullerene.</p><p>Thank you in advance. </p><p>_________________________ </p><p><strong>ffoplsaa.atp</strong></p><p> opls_141B 12.01100 ; fullerene</p>
<p>__________________________</p><p><strong>ffoplsaanb.itp</strong></p><p>; name bond_type mass charge ptype sigma epsilon</p><p>opls_141B C3 6 12.01100 0.000 A 3.47000e-01 2.76470e-01</p>
<p>__________________________</p><p><strong>ffoplsaa.rtp</strong></p><p>[ FUL ]<br> [ atoms ]<br> CF1 opls_141B 0.000 1<br> CF2 opls_141B 0.000 1<br> CF3 opls_141B 0.000 1<br> CF4 opls_141B 0.000 1<br>
CF5 opls_141B 0.000 1<br> CF6 opls_141B 0.000 1<br> .........<br> CF60 opls_141B 0.000 1<br> [ bonds ]<br> CF1 CF2<br> CF2 CF3<br> CF3 CF9<br> CF5 CF6<br> CF7 CF18<br> CF8 CF20<br>
CF10 CF14<br> CF11 CF24<br> CF13 CF26<br> CF15 CF28<br> CF17 CF30</p><p>..................<br> CF19 CF21<br> CF21 CF31<br> CF23 CF32<br> CF25 CF34<br> .............</p><p>____________</p><p><strong>ffoplsaabon.itp</strong></p>
<p>[ bondtypes ]<br>; i j func b0 kb<br> C3 C3 1 0.14200 265265.6</p><p>[ angletypes ]<br>; i j k func th0 cth<br> C3 C3 C3 1 114.000 488.273 ;</p><p>
[ dihedraltypes ]<br>; i j k l func coefficients<br> C3 C3 C3 C3 3 -4.96013 6.28646 1.30959 -2.63592 0.00000 0.00000 ; fullerene<br><br><br><br></p><p><br> <br><br></p></div>