<div dir="ltr">Thanks Nico. I tried -5000 but still all of my frequencies are real! I tried the ethane example (https://www.cp2k.org/exercises:2016_uzh_cmest:path_optimization_neb) and did full and partial frequency calculations separately. For the full frequency case, I obtained three imaginary frequencies (304.8i cm-1, 142.5i cm-1, and 103.4i cm-1) however when I froze H3 and H4 and did mode_selective calculations all calculated frequencies became real. The relevant parts of my input and output files for the partial frequency run of ethane are pasted below. I can post my input and output for the full frequency case as well if needed.<div><br></div><div>Many thanks,</div><div>Mohammad</div><div><br></div><div><b>Input</b>: </div><div><div><font color="#666666">.</font></div><div><font color="#666666">.</font></div><div><font color="#666666">.</font></div><div><font color="#666666">&MOTION</font></div><div><font color="#666666"> &CONSTRAINT</font></div><div><font color="#666666"> &FIXED_ATOMS</font></div><div><font color="#666666"> COMPONENTS_TO_FIX XYZ</font></div><div><font color="#666666"> LIST 3..4</font></div><div><font color="#666666"> &END FIXED_ATOMS</font></div><div><font color="#666666"> &END CONSTRAINT</font></div><div><font color="#666666">&END MOTION</font></div></div><div><font color="#666666">.</font></div><div><font color="#666666">.</font></div><div><font color="#666666">.</font></div><div><div><font color="#666666">&VIBRATIONAL_ANALYSIS</font></div><div><font color="#666666"> NPROC_REP 16</font></div><div><font color="#666666"> &MODE_SELECTIVE</font></div><div><font color="#666666"> ATOMS 1 2 5 6 7 8 </font></div><div><font color="#666666"> FREQUENCY -5000</font></div><div><font color="#666666"> RANGE -5000 10</font></div><div><font color="#666666"> &INVOLVED_ATOMS </font></div><div><font color="#666666"> INVOLVED_ATOMS 1 2 5 6 7 8</font></div><div><font color="#666666"> RANGE -5000 10</font></div><div><font color="#666666"> &END INVOLVED_ATOMS</font></div><div><font color="#666666"> &END MODE_SELECTIVE</font></div></div><div><font color="#666666">.</font></div><div><font color="#666666">.</font></div><div><font color="#666666">.</font></div><div><br></div><div><b>Output</b>:</div><div><br></div><div><div><font color="#666666"> REPLICA| layout of the replica grid, number of groups 1</font></div><div><font color="#666666"> REPLICA| layout of the replica grid, size of each group 16</font></div><div><font color="#666666"> REPLICA| MPI process to grid (group,rank) correspondence:</font></div><div><font color="#666666"> ( 0 : 0, 0) ( 1 : 0, 1) ( 2 : 0, 2) ( 3 : 0, 3)</font></div><div><font color="#666666"> ( 4 : 0, 4) ( 5 : 0, 5) ( 6 : 0, 6) ( 7 : 0, 7)</font></div><div><font color="#666666"> ( 8 : 0, 8) ( 9 : 0, 9) ( 10 : 0, 10) ( 11 : 0, 11)</font></div><div><font color="#666666"> ( 12 : 0, 12) ( 13 : 0, 13) ( 14 : 0, 14) ( 15 : 0, 15)</font></div><div><font color="#666666"> MS| ITERATION STEP 1</font></div><div><font color="#666666"> MS| TRACKED MODE 1252.008036cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 2</font></div><div><font color="#666666"> MS| TRACKED MODE 769.913197cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 3</font></div><div><font color="#666666"> MS| TRACKED MODE 439.855194cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 4</font></div><div><font color="#666666"> MS| TRACKED MODE 405.817333cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 5</font></div><div><font color="#666666"> MS| TRACKED MODE 331.609693cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 6</font></div><div><font color="#666666"> MS| TRACKED MODE 307.669620cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 7</font></div><div><font color="#666666"> MS| TRACKED MODE 299.612607cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 8</font></div><div><font color="#666666"> MS| TRACKED MODE 269.847744cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 9</font></div><div><font color="#666666"> MS| TRACKED MODE 223.476957cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| ITERATION STEP 10</font></div><div><font color="#666666"> MS| TRACKED MODE 164.744189cm-1 NOT CONVERGED</font></div><div><font color="#666666"> MS| DAVIDSON ALGORITHM CONVERGED</font></div><div><font color="#666666"> MS| TRACKED FREQUENCY (1) IS: 113.384782 cm-1</font></div><div><font color="#666666"><br></font></div><div><font color="#666666"> -------------------------------------------------------------------------------</font></div><div><font color="#666666"> FREQUENCY AND CONVERGENCE LIST</font></div><div><font color="#666666"> FREQUENCY MAXVAL CRITERIA NORM CRITERIA CONVERGENCE</font></div><div><font color="#666666"> VIB| 113.385 0.154191E-06 0.347E-06 YES</font></div><div><font color="#666666"> VIB| 352.500 0.138434E-06 0.311E-06 YES</font></div><div><font color="#666666"> VIB| 693.978 0.260601E-06 0.586E-06 YES</font></div><div><font color="#666666"> VIB| 1032.631 0.252407E-06 0.568E-06 YES</font></div><div><font color="#666666"> VIB| 1265.788 0.132026E-05 0.300E-05 NO</font></div><div><font color="#666666"> VIB| 1374.797 0.418727E-06 0.942E-06 YES</font></div><div><font color="#666666"> VIB| 1463.690 0.148252E-06 0.337E-06 YES</font></div><div><font color="#666666"> VIB| 2992.320 0.695927E-08 0.156E-07 YES</font></div><div><font color="#666666"> VIB| 3040.591 0.168953E-06 0.384E-06 YES</font></div><div><font color="#666666"> VIB| 3062.286 0.103910E-06 0.234E-06 YES</font></div><div><font color="#666666"> VIB| 3067.058 0.373819E-06 0.841E-06 YES</font></div><div><font color="#666666"><br></font></div><div><font color="#666666"> -------------------------------------------------------------------------------</font></div><div><font color="#666666"> - -</font></div><div><font color="#666666"> - DBCSR STATISTICS -</font></div><div><font color="#666666"> - -</font></div><div><font color="#666666"> -------------------------------------------------------------------------------</font></div><div><br></div><br>On Wednesday, 31 October 2018 00:23:17 UTC-7, Nico Holmberg wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;">Hi,<p>The range keyword should indeed fix the issue. Try setting the lower value to something smaller e.g. -5000.</p><p>-Nico</p><p></p></blockquote></div></div>