Subject: Again about CASSCF geometry optimization

From: cgliu <[email-masked]>
Date: Mon, 26 Mar 2001 20:36:25 +0800

Dear cclers:

I got some suggestions for my last question on this topic. I am sorry I had not stated it clearly.

I am doing a CASSCF optimization of Decapentaene( C10H12), to find the gometry of the ground state and the first excited state structure.

The program I used is Gaussian 98

For the first excited state structure. I took the following steps:

1) UHF optimization to find a rough geomtry which will be used as a starting geomtry in the next step
2) CASSCF(10,10)/3-21g single point calculation to find if it is necessary to alter the sequence of the orbitals.
3) The active space is compose of the ten pi and pi* molecular orbitals.
3) CASSCF(10,10)/3-21g guess=(alter,read) geom=check opt iop(1/8=3) to do geometry optimization with very small step size.

Unfortunately, after 2 steps of optimization. The abnormal result of MC-SCF result was reached, which looks like:

 Step scaled by    0.1350669311289174
 ITN=  1 MaxIt= 64 E=   -364.8936812240 DE=-3.65D+02 Acc= 1.00D-08 Lan=  1
 ITN=  2 MaxIt= 64 E=   -366.1983086710 DE=-1.30D+00 Acc= 1.00D-08 Lan=  1
 ITN=  3 MaxIt= 64 E=   -367.3423713309 DE=-1.14D+00 Acc= 1.00D-08 Lan=  1
 ITN=  4 MaxIt= 64 E=   -368.3968198326 DE=-1.05D+00 Acc= 1.00D-08 Lan=  1
 ITN=  5 MaxIt= 64 E=   -369.5356108067 DE=-1.14D+00 Acc= 1.00D-08 Lan=  1
 ITN=  6 MaxIt= 64 E=   -370.4283645295 DE=-8.93D-01 Acc= 1.00D-08 Lan=  1
 ITN=  7 MaxIt= 64 E=   -371.0982314618 DE=-6.70D-01 Acc= 1.00D-08 Lan=  1
 ITN=  8 MaxIt= 64 E=   -371.5249216994 DE=-4.27D-01 Acc= 1.00D-08 Lan=  1
 ITN=  9 MaxIt= 64 E=   -372.1397979687 DE=-6.15D-01 Acc= 1.00D-08 Lan=  1
 ITN= 10 MaxIt= 64 E=   -372.4663398452 DE=-3.27D-01 Acc= 1.00D-08 Lan=  1
 ITN= 11 MaxIt= 64 E=   -372.6890832012 DE=-2.23D-01 Acc= 1.00D-08 Lan=  1
 TTN= 12 MaxIt= 64 E=   -372.7988003755 DE=-1.10D-01 Acc= 1.00D-08 Lan=  1
 ITN= 13 MaxIt= 64 E=   -372.8776810015 DE=-7.89D-02 Acc= 1.00D-08 Lan=  1
 ITN= 14 MaxIt= 64 E=   -372.9287242959 DE=-5.10D-02 Acc= 1.00D-08 Lan=  1
 ITN= 15 MaxIt= 64 E=   -372.9442106552 DE=-1.55D-02 Acc= 1.00D-08 Lan=  1
 ITN= 16 MaxIt= 64 E=   -372.9578164278 DE=-1.36D-02 Acc= 1.00D-08 Lan=  1
 ITN= 17 MaxIt= 64 E=   -372.9619686829 DE=-4.15D-03 Acc= 1.00D-08 Lan=  1
 ITN= 18 MaxIt= 64 E=   -372.9642236498 DE=-2.25D-03 Acc= 1.00D-08 Lan=  1
 ITN= 19 MaxIt= 64 E=   -372.9652195918 DE=-9.96D-04 Acc= 1.00D-08 Lan=  1
 ITN= 20 MaxIt= 64 E=   -372.9656045045 DE=-3.85D-04 Acc= 1.00D-08 Lan=  1
 ITN= 21 MaxIt= 64 E=   -372.9661566455 DE=-5.52D-04 Acc= 1.00D-08 Lan=  1
 ITN= 22 MaxIt= 64 E=   -372.9661928826 DE=-3.62D-05 Acc= 1.00D-08 Lan=  1
 ITN= 23 MaxIt= 64 E=   -372.9661961859 DE=-3.30D-06 Acc= 1.00D-08 Lan=  1
 ITN= 24 MaxIt= 64 E=   -372.9661963454 DE=-1.60D-07 Acc= 1.00D-08 Lan=  1
 ITN= 25 MaxIt= 64 E=   -372.9661964451 DE=-9.97D-08 Acc= 1.00D-08 Lan=  1
 ITN= 26 MaxIt= 64 E=   -372.9661964510 DE=-5.87D-09 Acc= 1.00D-08 Lan=  1
 ... DO AN EXTRA-ITERATION FOR FINAL PRINTING
          ( 1)     EIGENVALUE    -0.37296620E+03
 (    1) 0.8546868 (  232)-0.1605760 (   18) 0.1273223 (  214)-0.1203281 (   29)
 0.1085574 (  327) 0.1014540 (  348)-0.0957454
 ( 8257)-0.0880574 ( 1545) 0.0854231 ( 7879)-0.0851818 ( 7881)-0.0818381 (   20)
 0.0795558 (   68)-0.0769911 ( 1771) 0.0741894
 ( 8780) 0.0631177 (  334) 0.0609166 (  244)-0.0540400 (   75)-0.0520658 ( 2018)
-0.0480310 (   63)-0.0473743 ( 8283) 0.0436091
 (  375)-0.0435983 (  359) 0.0423989 (  265)-0.0423721 ( 1797)-0.0420108 ( 1626)
-0.0403186 ( 1856) 0.0401087 (  253) 0.0399931
 ( 2039) 0.0399314 ( 8801)-0.0386601 ( 7898) 0.0378718 ( 8269)-0.0377589 (  234)
 0.0369503 ( 8787) 0.0363671 ( 8908)-0.0355514
 ( 2077)-0.0352455 ( 8030) 0.0348422 ( 8540)-0.0347887 (  236)-0.0330726 ( 8004)
-0.0328432 ( 8643)-0.0324733 (  298)-0.0324499
 ( 1888)-0.0316934 ( 8775)-0.0311804 ( 8839) 0.0292843 ( 1564)-0.0292114 (  403)
-0.0287844 (   88)-0.0286648 ( 8656) 0.0286427
 ( 8142)-0.0286416 (
 Final one electron symbolic density matrix:
   12345
   1  0.000000D+00
   2  0.000000D+00  0.000000D+00
   3  0.000000D+00  0.000000D+00  0.000000D+00
   4  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
   5  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
   6  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
   7  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
   8  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
   9  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
  10  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
             6             7             8             9            10
   6  0.000000D+00
   7  0.000000D+00  0.000000D+00
   8  0.000000D+00  0.000000D+00  0.000000D+00
   9  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
  10  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00  0.000000D+00
 MCSCF converged.

=============================> The above matrix elements are all zero.

The followed gradient calculation was of course failed. It produced a very large negative eigenvalue. The optimization go unreasonably next, and failed in several steps.  
 
I would appreciate your advice about it.

By the way, is unrestricted DFT an acceptable method for the calculation of the first triplet state geometry? I computed some structures and found that the geometries obtained from DFT were very close the the CASSCF result with respect to the CIS calculation. 

Best regards,

Chungen Liu

______________________________________
Chungen Liu, Dr.
Chemistry Department
Nanjing University

===================================================================
(http://mail.sina.com.cn)
(http://newchat.sina.com.cn)

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From: petra imhof <[email-masked]>
Date: Mon, 26 Mar 2001 22:23:34 +0200

At 20:36 26.03.01 +0800, you wrote:
>I am doing a CASSCF optimization of Decapentaene( C10H12), to find the
gometry of the ground state and the first excited state structure.
>The program I used is Gaussian 98
Though it will not help you:
you are not the first one who tries in vain to run a CASSCF calculation
with this number of CSFs using Gaussian. 
"Promises" of CASSCF calculations with up to 12 orbitals are not kept -or
maybe with only two electrons? At least to my knowledge no one ever
published the iops necessary for this.

I wonder how M. Klene, M.A. Robb, P. Celani and M. J. Frisch managed the
(14,14) calculation they reported as example for parallelization (J. Chem.
Phys. 113 (2000) 5653).

(If anyone "official" of Gaussian Inc. is reading- if you please have the
answer...)

Sorry for not helping but only complaining,
Petra
http://www-public.rz.uni-duesseldorf.de/~imhof/

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From: Lakshmi Devi Kesavan <[email-masked]>
Date: Mon, 26 Mar 2001 15:28:56 -0600 (CST)

Hello all,

	I am looking for PM3 parameters for the transition metal 'Fe'.   

Thanking you in advance,

Lakshmi Kesavan.

************************* 
Lakshmi S Devi Kesavan 
Graduate Student 		
Department of Chemistry		
207, Pleasant Street S.E,  
University of Minnesota	 
Minneapolis, MN 55455-0431

Off # : 612-625-5325			
*************************