finite-difference frequencies
Peter Knowles
peterk at tc.bham.ac.uk
Wed May 9 20:52:46 BST 2001
This bug (if you really care,
http://www.tc.bham.ac.uk/bugzilla/show_bug.cgi?id=48) was recently
fixed in the development version of the code, but we haven't also made
a patch for 2000.1 since we hope that 2000.1 will be history soon. If
you vote that you would like the fix now, we'll make the patch.
Peter
Charles Doubleday wrote at 15:09 on 9 May 2001:
> Molpro apparently has a bug in its finite-difference frequency code.
> The Molpro 2000.1 manual lists the following example in which the input
> file h2o_freqdft.com produces an output file h2o_freqdft.out.
>
> "h2o_freqdft.com":
>
> geometry={O; !Z-matrix for water
> H1,O,R;
> H2,O,R,H1,THETA}
> R=0.96 Ang !start bond distance
> Theta=104 !start bond angle
> basis=6-31g** !Pople basis set
> functional=b3lyp !define fucntional (optional, b3lyp is
> default)
> freqdft !run frequency calculation
>
> frequencies from "h2o_freqdft.out"
>
> Imaginary Vibration Wavenumber
> Nr [1/cm]
> 1 62.30
> 2 62.30
> 3 23.57
>
> Low Vibration Wavenumber
> Nr [1/cm]
> 1 1.60
>
> Vibration Wavenumber
> Nr [1/cm]
> 1 1052.45
> 2 1660.40
> 3 2322.20
> 4 2964.69
> 5 3794.43
>
>
> "freqdft" is evidently a macro that first optimizes H2O (gradmax =
> 2.6e-4 au) and computes frequencies at the optimized geometry. The
> program appears to have a bug because it gives 5 frequencies. In
> addition, it does not project out translations and rotations. Also,
> where is "freqdft" documented?
>
> Thanks,
> Charles Doubleday
> <!doctype html public "-//w3c//dtd html 4.0 transitional//en">
> <html>
> <tt>Molpro apparently has a bug in its finite-difference frequency code.
> The Molpro 2000.1 manual lists the following example in which the input
> file h2o_freqdft.com produces an output file h2o_freqdft.out.</tt>
> <p><tt>"h2o_freqdft.com":</tt>
> <p><tt>geometry={O;
> !Z-matrix for water</tt>
> <br><tt> H1,O,R;</tt>
> <br><tt> H2,O,R,H1,THETA}</tt>
> <br><tt>R=0.96 Ang
> !start bond distance</tt>
> <br><tt>Theta=104
> !start bond angle</tt>
> <br><tt>basis=6-31g**
> !Pople basis set</tt>
> <br><tt>functional=b3lyp
> !define fucntional (optional, b3lyp is default)</tt>
> <br><tt>freqdft
> !run frequency calculation</tt>
> <p><tt>frequencies from "h2o_freqdft.out"</tt>
> <p><tt> Imaginary Vibration Wavenumber</tt>
> <br><tt> Nr
> [1/cm]</tt>
> <br><tt> 1
> 62.30</tt>
> <br><tt> 2
> 62.30</tt>
> <br><tt> 3
> 23.57</tt>
> <p><tt> Low Vibration Wavenumber</tt>
> <br><tt> Nr
> [1/cm]</tt>
> <br><tt> 1
> 1.60</tt>
> <p><tt> Vibration
> Wavenumber</tt>
> <br><tt> Nr
> [1/cm]</tt>
> <br><tt> 1
> 1052.45</tt>
> <br><tt> 2
> 1660.40</tt>
> <br><tt> 3
> 2322.20</tt>
> <br><tt> 4
> 2964.69</tt>
> <br><tt> 5
> 3794.43</tt>
> <br>
> <p><tt>"freqdft" is evidently a macro that first optimizes H2O (gradmax
> = 2.6e-4 au) and computes frequencies at the optimized geometry.
> The program appears to have a bug because it gives 5 frequencies.
> In addition, it does not project out translations and rotations.
> Also, where is "freqdft" documented?</tt><tt></tt>
> <p><tt>Thanks,</tt>
> <br><tt>Charles Doubleday</tt></html>
--
Prof. Peter J. Knowles
Email P.J.Knowles at bham.ac.uk Phone +44-121-414-7472 Fax +44-121-414-7471
School of Chemistry, Univ. of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
WWW http://www.tc.bham.ac.uk/~peterk/
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