Convergence issues


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Forum Vet
It seems that the projection from a small basis to a large basis with linear dependencies is creating some problems. I don't know why you have to do the projection because either the cc-pVDZ or aug-cc-pVDZ converge in 9 iterations starting from a default atomic guess, using the input below.

Bert


start phenanthrene
geometry
 C                  0.00000000    2.84859800    0.88680600
C 0.00000000 3.57955900 -0.29438700
C 0.00000000 2.89936800 -1.53469700
C 0.00000000 1.50842000 -1.57667000
C 0.00000000 0.73043500 -0.38774400
C 0.00000000 1.42795200 0.87014000
C 0.00000000 -0.73043500 -0.38774400
C 0.00000000 -1.42795200 0.87014000
C 0.00000000 -0.68487000 2.10145900
C 0.00000000 0.68487000 2.10145900
C 0.00000000 -1.50842000 -1.57667000
C 0.00000000 -2.89936800 -1.53469700
C 0.00000000 -3.57955900 -0.29438700
C 0.00000000 -2.84859800 0.88680600
H 0.00000000 3.35683000 1.85437700
H 0.00000000 4.67108900 -0.26819800
H 0.00000000 -1.24321500 3.04075300
H 0.00000000 1.24321500 3.04075300
H 0.00000000 -1.01691100 -2.54926800
H 0.00000000 -3.46767400 -2.46710500
H 0.00000000 -4.67108900 -0.26819800
H 0.00000000 -3.35683000 1.85437700
H 0.00000000 3.46767400 -2.46710500
H 0.00000000 1.01691100 -2.54926800
symmetry c2v
end

basis "small" spherical
 H library cc-pVDZ
C library cc-pVDZ
end

basis "large" spherical
 H library aug-cc-pVDZ
C library aug-cc-pVDZ
end

set "ao basis" small

dft
 xc becke88 1.0 lyp 1.0
tolerances tight
direct
iterations 100
end

task dft energy

set "ao basis" large

dft
 xc becke88 1.0 lyp 1.0
tolerances tight
direct
iterations 100
end

task dft energy