MP2 optimization failure

[Eric]

Dear Prof,

MP2 optimization on CH2CCH2+ failed. The nw file is shown below while the output is attached. How can I fix this? Thanks in advance!

start CH2CCH2+

title 'CH2CCH2+'

charge 1.0

geometry units angstrom

  load CH2CCH2+.xyz

end

basis

  * library 6-31G(2df,p) 

end 

scf

  uhf

  doublet

end 

driver

  maxiter 199

  xyz CH2CCH2+

end

task dft optimize

[Edoardo Aprà]

Input and output files are not consistent with each other (in other words, the input file  you posted cannot produce the posted output file).

You might want to add the echo keyword (at the beginning of the output file) to echo the input file into the output file

https://nwchemgit.github.io/ECHO.html

[Eric]

Thank you for the tips. The attached file should be the right one.

[Edoardo Aprà]

I would keep the symmetry and simply modify the coordinates to lower the symmetry (from D2d to C2v).

This modified input does not crash as the original one

start CH2CCH2+
echo

title 'CH2CCH2+'
charge 1.0
geometry units angstrom

#  load CH2CCH2+.xyz
 C                     0.00000000     0.00000000     0.00000000
 C1                    0.00000000     0.00000000     1.30139300
 C                     0.00000000     0.00000000    -1.30139300
 H                    -0.65465855     0.65465855     1.86940900
 H                     0.65465855    -0.65465855     1.86940900
 H                     0.65465855     0.65465855    -1.86940900
 H                    -0.65465855    -0.65465855    -1.86940900
end
basis spherical

  * library 6-31G(2df,p)
end
scf
  uhf
  doublet

  maxiter 199
#  sym off
#  adapt off

end
driver
  maxiter 199
  xyz CH2CCH2+
end

task mp2 optimize