Subject: NWchem: optimization problem

From: "ELAMBALASSERY, JAYASREE" <jayaeg..at..berkeley.edu>
Date: Mon, 06 Dec 2004 09:07:35 -0800

Dear all,

I tried an optimization job of simple molecule (allyl fluoride) using NWChem 4.5. It reproduced 
the energy and geometry which I got from Gaussian calculations. I ran the above job in DATASTAR at 
San Diego (SDSC IBM DataStar Power4). Now I tried running another job but it converges to a point 
far away from the minimum and gives me more than 70 imaginary frequency. When I tried with tight 
convergence, it converged to another point with 28 imaginary frequencies. The input is attached 
below. Can you pls tell me where I went wrong? Gaussian optimized geometry is taken as the input 
in this case. Thank you very much
Jayasree

******************input***********************
scratch_dir /scratch

permanent_dir .

restart 14cot

title "14cot"

geometry units angstroms autosym
  C 1.22985 -1.06641 0.68744
  H 1.69955 -1.7696 1.37073
  C 1.37469 0.24475 0.93719
  H 1.96198 0.55484 1.79803
  C 0.55145 -1.65633 -0.46926
  C -0.75312 -1.40745 -0.71867
  H -1.25431 -1.89237 -1.5518
  C 0.85554 1.31703 0.12136
  C -0.44029 1.52588 -0.16094
  H -0.69626 2.39261 -0.7653
  C -1.57038 0.73206 0.32788
  C -1.66695 -0.58888 0.05984
  H -2.53628 -1.15259 0.38683
  H 1.59529 2.02231 -0.2494
  C 1.42464 -2.59451 -1.34568
  C -2.63907 1.52066 1.1321
  C 0.73672 -3.02544 -2.66467
  H 1.40752 -3.63935 -3.27799
  H 0.44955 -2.15745 -3.26953
  H -0.15884 -3.62886 -2.47703
  C -3.39844 2.48878 0.19959
  H -2.74376 3.26394 -0.21267
  H -4.20243 3.00506 0.73744
  H -3.85363 1.95249 -0.64122
  C 1.76236 -3.88525 -0.56889
  H 2.32203 -4.58846 -1.19697
  H 0.8515 -4.39417 -0.23257
  H 2.38021 -3.68676 0.31332
  C 2.74101 -1.8895 -1.74832
  H 3.33964 -2.52087 -2.41564
  H 3.37038 -1.66322 -0.88039
  H 2.54052 -0.94848 -2.27392
  C -3.69901 0.61424 1.8056
  H -3.23345 -0.11726 2.47634
  H -4.2995 0.07297 1.06546
  H -4.39935 1.20555 2.40801
  C -1.97253 2.33284 2.26704
  H -1.29743 3.10466 1.88085
  H -1.39406 1.68103 2.93223
  H -2.72321 2.84787 2.8782
end

basis
  C Library 6-31++G*
  H Library 6-31++G*
end

scf
  rhf
  singlet
end

driver
  maxiter 200
  tight
end

task scf optimize

task scf freq

******
Elambalassery G. Jayasree
Prof Streitwieser group
University of California
Berkeley-94720
Ph (510) 642-0796.