<div dir="ltr">Hi<div><br></div><div>In addition to what Matt said, if you really want to compare results from CP2K and Gaussian, you should: (1) use the all-electron method, i.e. GAPW, in CP2K; (2) use the same basis sets; (3) use the same method to calculate frequencies. For (3), Gaussian calculates frequencies analytically by default, while CP2K calculates frequencies numerically. To calculate frequencies numerically in Gaussian, you should specify Freq=Numer. And also the calculated frequencies may be sensitive to the the step size for numerical differentiation, therefore, you should use the same step size in both calculations. In Gaussian, this is controlled by the Step keyword, see <a href="http://www.gaussian.com/g_tech/g_ur/k_freq.htm">http://www.gaussian.com/g_tech/g_ur/k_freq.htm</a>; in CP2K, this is controlled by the DX keyword.</div><div><br></div><div>SL</div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 24 November 2016 at 10:05, Matt W <span dir="ltr"><<a href="mailto:MattWa...@gmail.com" target="_blank">MattWa...@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi,<div><br></div><div>you are not consistently running a non-periodic system - you need a nonperiodic poisson section too. And </div><div><br></div><div>1. You have </div><div><br></div><div><div>&VIBRATIONAL_ANALYSIS</div><div> DX 1.0E-03</div><div> NPROC_REP 24</div><div> FULLY_PERIODIC TRUE</div><div><br></div><div>the fully periodic keyword means that CP2K won't remove rotations (because they aren't there for a crystal with pbc) - so you get an extra 3 modes.</div><div><br></div><div>2. You are running a totally different 'model chemistry' in Gaussian terminology. You can't compare M062X with PBE directly. PBE (GGAs) typically underbind, bonds too long, frequencies too small. M06 maybe is better on average.</div><div><br></div><div>3 So you are mixing two things - accurate, i.e. properly performed calculation at a given level of theory - and agreement with experiment. Changing the model will change the frequencies. Changing settings (CUTOFF mainly, probably) will just ensure you get the correct numbers for the model. You should run PBE in Gaussian to compare to, if this is what you want.</div><span class="HOEnZb"><font color="#888888"><div><br></div><div>Matt</div></font></span><div><div class="h5"><br>On Wednesday, November 23, 2016 at 9:40:31 PM UTC, J. Ye wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi all, <div><br></div><div>I calculate frequency for small molecules and try to compare with Gaussian 09 and experimental results. I show the results from <b>CP2K </b>(PBE functional-BASIS_MOPLOT, GTH potental, nonperiodic) and <b> Gaussian09 </b>(M062X/6-311g(d,p)) . </div><div><br></div><div>I have several questions:</div><div><br></div><div>1. You will see the total number of modes obtained from CP2K is 15, however 12 modes from Gaussian. Are the first three modes are translation modes or rotation modes for C2H4?</div><div><div>2. If we only compare the 12 vibration modes, the value for most of modes from Gaussian is larger than CP2K. What's the reason for getting smaller frequencies from CP2K? </div><div>3. What is the keyword can strongly affect the frequencies? Affect the accuracy of frequencies? </div><div><br></div><div>Thanks very much! </div><div><br></div><div><table border="0" cellpadding="0" cellspacing="0" width="128" style="border-collapse:collapse;width:96pt">
<colgroup><col width="64" span="2" style="width:48pt">
</colgroup><tbody><tr height="20" style="height:15.0pt">
<td height="20" width="64" style="height:15.0pt;width:48pt">CP2K</td>
<td width="64" style="width:48pt">Gaussian</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" style="height:15.0pt">c2h4</td>
<td></td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" colspan="2" style="height:15.0pt">15
modes </td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">-19.0703</td>
<td></td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">-5.64472</td>
<td></td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">19.50384</td>
<td></td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">807.9613</td>
<td align="right">831.8134</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">942.954</td>
<td align="right">988.1607</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">995.6397</td>
<td align="right">996.8044</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">1045.988</td>
<td align="right">1071.741</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">1206.11</td>
<td align="right">1239.784</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">1373.488</td>
<td align="right">1386.642</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">1446.925</td>
<td align="right">1470.955</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">1646.778</td>
<td align="right">1717.766</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">3158.382</td>
<td align="right">3156.212</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">3171.654</td>
<td align="right">3172.992</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">3269.88</td>
<td align="right">3235.274</td>
</tr>
<tr height="20" style="height:15.0pt">
<td height="20" align="right" style="height:15.0pt">3270.754</td>
<td align="right">3260.871</td>
</tr></tbody></table></div></div></div></blockquote></div></div></div></div><div class="HOEnZb"><div class="h5">
<p></p>
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