[molpro-user] mrci CH stretch dipole incorrect?

[Bryan Matthew Wong]

Hi,

     I am trying to calculate the MRCI dipole moment for stretching one of
the CH bonds for linear acetylene (HCCH). As I stretch one of the CH bonds,
the dipole moment increases from 0 to 0.38 debye at 1.8 Angstroms, and
decreases to -0.65 Angstroms at around 3.2 Angstroms.  This clearly can't be
correct since the dipole moment of the CCH radical at the same level of
theory is 0.7 Debye (all molecules are oriented in the same direction so the
change in dipole moment sign is very incorrect).  Does anyone know what is
wrong?  I have included a sample input for the 2.2 Angstrom case.

Bryan


CC=1.21120500
H1C2=2.2
H2C1=1.06408640

geometry={;ang;noorient;
C1
C2,C1,CC
X1,C2,1.00,C1,90.0
H1,C2,H1C2,X1,90.0,C1,180.0
X2,C1,1.00,C2,90.0,X1,180.0
H2,C1,H2C1,X2,90.0,C2,180.0};

basis
  default=aug-cc-pvqz
end

rhf
mcscf
mrci
optg;inactive,H1C2
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