Molcas Forum

PabloR0

Member

Registered: 2022-05-27

Posts: 2

[SOLVED] Geometry optimization - SLAPAF: "Error in Int2Car"

Dear MOLCAS forum and developers,

We have been trying to do a geometry optimization of a (2E)-3-(Dibenzylamino)acrylonitrile but we encountered every time this error after n-th SLAPAF iteration:

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 ###    Error in Int2Car                                                                                                                     ###
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 ***********************************************
  ERROR: No convergence in Int2Car !
  Strong linear dependency among Coordinates.
  Hint: Try to change the Internal Coordinates.
 ***********************************************

We want to compute a PES following a dihedral angle C1 N1 C3 C4 (initial angle: -180°).

The starting geometry presented the same problem (with no constraints) so it was optimized using Gaussian then these new coordinates (in the output below) were fed to MOLCAS 8.0.

We tried optimizing, each time in minimal basis (as in the output below) OR in normal basis (3s2p for N and C, 2s for H) using constraints:
- only dihedral                                                       - at SCF level
                                                                              - at MBPT2 level

- dihedral + all C-H bonds fixed at 1.09 A             - at SCF level
                                                                              - at MBPT2 level

Depending on the conditions, SLAPAF runs until 5 to 17 iterations before stopping with this error.

We tried a lot of different inputs but all resulted in the same error in the end. ALASK runs nicely but SLAPAF stops with this Int2Car error.

Here is our input:

>>> Export MOLCAS_MAXITER=200

 &GATEWAY
 title
DAMN optimized in DFT

Coord
35

N1    -0.473538    0.915416    0.094824    Angstrom
N2    -4.306966    3.838252    0.217443    Angstrom
H1    -1.335504    2.396115    1.217477    Angstrom
H2    -2.869466    1.412504   -1.271308    Angstrom
H3     0.339353   -0.316633    1.593599    Angstrom
H4     0.408753    1.409856    1.908947    Angstrom
H5     1.695172    2.608685   -0.360701    Angstrom
H6     4.016229    2.701110   -1.222768    Angstrom
H7     5.585195    0.828394   -0.773413    Angstrom
H8     4.816724   -1.135597    0.537891    Angstrom
H9     2.494386   -1.222257    1.393832    Angstrom
H10    0.509103   -0.058442   -1.454930    Angstrom
H11   -1.153814    0.356519   -1.796002    Angstrom
H12    1.032267   -2.288523   -0.961544    Angstrom
H13    0.387209   -4.555077   -0.203391    Angstrom
H14   -1.920595   -4.982260    0.613931    Angstrom
H15   -3.572534   -3.128791    0.665952    Angstrom
H16   -2.923781   -0.867806   -0.087724    Angstrom
C1     0.531835    0.656325    1.128397    Angstrom
C2    -0.493526   -0.033895   -1.021641    Angstrom
C3    -1.487551    1.785395    0.332634    Angstrom
C4    -2.620006    1.993987   -0.392356    Angstrom
C5     1.947710    0.696645    0.590875    Angstrom
C6     2.385211    1.795531   -0.155555    Angstrom
C7     3.687498    1.842775   -0.644939    Angstrom
C8     4.569448    0.790465   -0.392783    Angstrom
C9     4.139417   -0.309581    0.345529    Angstrom
C10    2.831240   -0.356575    0.829773    Angstrom
C11   -0.904796   -1.428813   -0.593564    Angstrom
C12    0.020161   -2.475062   -0.613002    Angstrom
C13   -0.342251   -3.751702   -0.182416    Angstrom
C14   -1.634921   -3.990270    0.277893    Angstrom
C15   -2.563537   -2.948642    0.307387    Angstrom
C16   -2.200569   -1.675958   -0.123859    Angstrom
C17   -3.539559    3.003796   -0.023325    Angstrom


Basis= C.ano-rcc.Roos.14s9p4d3f2g.2s1p.,H.ano-rcc.Widmark.8s4p3d1f.1s.,N.ano-rcc.Roos.14s9p4d3f2g.2s1p.  


Group = NoSym

Constraints
a = Dihedral C1 N1 C3 C4
Values
a = 150. degrees
End of Constraints

>>> Do while
 &SEWARD
 &SCF
 &MBPT2
 frozen = 19
 &SLAPAF
>>> EndDo

I must admit running out of ideas, I tried to ask ALASKA for more verbose but I'm stuck with this error.

May I ask for your help regarding this problem ? I can give outputs if needed.

With my best regards and my deepest thanks,

Pablo ROSEIRO

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: [SOLVED] Geometry optimization - SLAPAF: "Error in Int2Car"

Try adding the "Cartesian" keyword to SLAPAF. That does not affect the constraints.

PabloR0

Member

Registered: 2022-05-27

Posts: 2

Re: [SOLVED] Geometry optimization - SLAPAF: "Error in Int2Car"

Thank you so much Ignacio, you solved my problem and everything is working well !

Have a wonderful day !