I am running MCSCF calculations for finally obtaining good electronic wavefunctions for later response calculations. Convergence of the electronic wavefuction is slow and I am looking for ways to speed things up. I wonder if reducing the threshold for the integrals maybe a good way.

From the manual of DALTON,

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```
*SUPINT
.THRESH
READ (LUCMD,*) THRSUP
Threshold for the supermatrix integrals. Read one more line containing the threshold.
Default is the same as the threshold for discarding the two-electron integrals (see the
chapter describing the molecule input format, Ch. 26).
```

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```
Integrals (Real). Indicates the threshold for which integrals smaller than this will
be considered to be zero. If not speciﬁed, a threshold of 1.0D-15 will be used. A
threshold of 1.0D-15 will give integrals correct to approximately 1.0D-13.
```

- 1. Are both parameters need to defined during the calculation or one is enough.

- 2. How to properly give input in the *.mol file.

For O2 I received this output (full file attached), at the end of the electronic part of the calculation,

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```
Magnitude of CI coefficients
============================
( Ranges are relative to norm of vector : 1.00E+00 )
10- 1 to 10- 0 6 0.88051459E+00 0.8805145941
10- 2 to 10- 1 152 0.87662190E-01 0.9681767840
10- 3 to 10- 2 3156 0.27643054E-01 0.9958198378
10- 4 to 10- 3 42066 0.37854091E-02 0.9996052469
10- 5 to 10- 4 292457 0.38256489E-03 0.9999878118
10- 6 to 10- 5 609481 0.12082055E-04 0.9999998939
10- 7 to 10- 6 357798 0.10591637E-06 0.9999999998
10- 8 to 10- 7 64140 0.23031285E-09 1.0000000000
10- 9 to 10- 8 8060 0.26174301E-12 1.0000000000
10-10 to 10- 9 4774 0.95959001E-15 1.0000000000
10-11 to 10-10 4490 0.10694157E-16 1.0000000000
Number of coefficients less than 10^-11 times norm is 3198
Total CPU time used in SIRIUS : 15 hours 55 minutes 26 seconds
Total wall time used in SIRIUS : 9 hours 24 minutes 15 seconds
```