Molcas Forum

cymantren

Member

Registered: 2017-09-18

Posts: 37

[SOLVED] Displacement along Normal coordinate

Hello Users and Developers,

how can one make a displacement along a normal-coordinate ?

For example, the TS of NH3, e.g. plan-NH3, should have one imaginary Frequency, but if one shift the N-Atom along this imag. Freq., this should disappear.

I used a B-Cluster, which has 1 imag. Freq. and therefore it is a TS-structure. How can I get rid of this ?

Thank you in advance for your kind help.

Best regards

Alfred

----------------------------------------------------------

>>> EXPORT MOLCAS_MAXITER = 150

>>> DO WHILE

  &GATEWAY
    XBAS=6-31G**
    ZMAT
    B1
    B2  1  1.8
    B3  2  1.8  1  60.0
    B4  3  1.8  2  120.0   1   0.0
    B5  1  1.8  3  120.0   4 180.0
    END OF ZMAT

  &SEWARD

  &SCF
    UHF
    ZSpin=1
    End of input

  &SLAPAF

  &ALASKA

>>> END DO

&MCKINLEY

----------------------------------

OUTPUT

---------------------------------
......

++ Principal components of the normal modes
   ----------------------------------------

   (Only contributions larger than 0.50 times the maximum are printed)


      Mode      1
        Frequency:         i227.02 cm-1
      ---------------------------------
        Bond B5 B2              -1.0000
        Bond B4 B3               0.9994
        Bond B4 B1              -0.7168
        Bond B5 B1               0.7161
      ---------------------------------

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,204

Re: [SOLVED] Displacement along Normal coordinate

Look at the freq.molden file, take the "vibration 1" coordinates and add them (multiplied by an appropriate factor) to your Cartesian coordinates.

cymantren

Member

Registered: 2017-09-18

Posts: 37

Re: [SOLVED] Displacement along Normal coordinate

Thank you Ignacio,

for your clear an short help !

Best regards

Alfred