vibrational frequency analysis for symmetric molecule

[chandra]

Hi,

I am looking at the optimization of -NH2 functionalized adamantane  molecule (cs symmetry) using DFT (PBE/def2-tzvp) method. I am able to optimize the structure. To confirm that the the optimized geometry that I have obtained is local minima I should perform vibrational frequency analysis. I tried  but unable to calculate the vibrational frequencies (please see the attached file). I am always getting an error. Please let me know what is the issue. In the manual it is mentioned that for high symmetric systems turbomole fails to calculate the hessain matrix/forces.  I also want to know if there is a way to confirm that the optimized structure that I obtained is minimum energy geometry without  calculating the vibrational frequeny analysis.

[antti_karttunen]

Hi,

It seems that the actual error message is not printed in the output. So, you would find it in a batch system log file or in your terminal. My guess is that this is a memory-related issue. Please see the following FAQ: http://www.turbo-forum.com/index.php/topic,23.0.html

In the manual it is mentioned that for high symmetric systems turbomole fails to calculate the hessain matrix/forces

I'm pretty sure that Turbomole has no problems for highly symmetric systems. Even some really high-symmetry point groups that do not exist in most programs work fine with aoforce (e.g. D_24h). The only case where I've encountered problems with aoforce is point groups with complex irreducible (E) representations. For those, aoforce prints a warning and you probably should use NumForce. However, Cs is certainly no problem.

I also want to know if there is a way to confirm that the optimized structure that I obtained is minimum energy geometry without  calculating the vibrational frequeny analysis.

To confirm the structure as true local minimum at the potential energy surface, you need to run a vibrational frequency analysis. Making sure that you have the lowest energy conformer/isomer is another type of problem and for this you need to systematically check the energies of other reasonable conformations/isomers.

Best,
Antti

[chandra]

Hi Antti,

Thank you for the reply. I increased the memory but it didn't help me. I got an error 137 and following lines are written in error.output.

/pfs/data4/software_fh2/bw/chem/turbomole/7.1_tmolex42/TURBOMOLE/bin/em64t-unknown-linux-gnu_smp/aoforce: line 40: 25104 Killed   $TURBODIR/bin/`sysname`/aoforce_omp $STROPT

Please find the attached input and output files. Let me know if i am missing anything in my input.

[chandra]

Following is my control file.

control file:

$lastdiag
$rundimensions
dim(fock,dens)=125226
   natoms=28
   nshell=189
   nbf(CAO)=498
   dim(trafo[SAO<-->AO/CAO])=968
   rhfshells=1
$energy    file=energy
$scfdump
$drvopt
cartesian  on
   basis      off
   global     off
   hessian    on
   dipole     on
   nuclear polarizability
$maxcor    5000
$dft
functional pbe
gridsize m3
$subtitle
SP,DFT/no-RI,PBE,charge 0,cs,def2-TZVP,FREQ
$dipole from dscf
  x     0.40232309308333    y     0.22808244082158    z    -0.00000000000001    a.u.
   | dipole | =    1.1755095280  debye
$scfiterlimit    30
$coord    file=coord
$jbas    file=auxbasis
$thime    5
$scfconv    6
$charge from dscf
          0.000 (not to be modified here)
$scforbitalshift    automatic=.1
$grad    file=gradient
$optimize
internal off
redundant off
cartesian on
global off
$symmetry    cs
$tmole
$basis    file=basis
$cosmo_out    file=job_notRun_65.cosmo
$scfmo   file=mos
$title    tmolecal
$atoms
h 11-17,19-28 \
   basis = h def2-TZVP
n 18 \
   basis = n def2-TZVP
c 1-10 \
   basis = c def2-TZVP
$scfdamp     start=0.700 step=0.050 min=0.100
$operating system unix
$thize    0.10000000E-04
$scfintunit
unit=30       size=0        file=twoint
$scfdiis
$last SCF energy change = -445.62776
$closed shells
a'      1-27                                   ( 2 )
a"      1-15                                   ( 2 )
$actual step      force
$orbital_max_rnorm 0.17612274894689E-04
$restart force
$end

[antti_karttunen]

Hi,

did you just increase $maxcor or also the user limits as explained in the FAQ (for example, ulimit -s unlimited)?

Antti