Molcas Forum

Slowloris

Member

Registered: 2017-09-01

Posts: 4

[SOLVED] RASSCF converge problem for a molecule with D2h symmetry

I am trying to run a rasscf calculation with active space cas(9,7). It seems sometime the computation can not converge, and sometimes the orbitals of active space is completely wrong after converge. I have been trying methods like increasing levshift to 1.5 or starting from minimal basis set, but the problem is still not solved. I am reading molcas manual about symmetry, it says the calculation can beak the original symmetry if the actual symmetry is higher than what's being applied for calculation. Since I am using no symmetry to calculate this D2h molecule, I am wondering if this is the origin of the problem. My input file is attached below.

&SEWARD
Douglas-Kroll
HIGH Cholesky
AMFI
RELI
RX2C
RBSS
ANGM
0	0	0	Angstrom

Basis Set
C.ANO-RCC-MB.
C1	2.9289	-1.6876	-0.5453 Angstrom
C3	6.1305	0.7681	5.1015	Angstrom
C5	4.8114	1.235	5.1747	Angstrom
C7	3.8649	0.9139	4.2212	Angstrom
C9	4.2929	0.0952	3.1672	Angstrom
C11	2.6971	-2.4078	-1.7281	Angstrom
C13	3.6824	-3.1871	-2.2912	Angstrom
C15	4.9478	-3.2648	-1.7082	Angstrom
C17	5.2128	-2.5709	-0.5516	Angstrom
C19	4.2101	-1.7851	0.0575	Angstrom
C21	4.5044	-1.1143	1.3041	Angstrom
C23	5.611	-0.3619	3.0981	Angstrom
C26	6.5601	-0.0378	4.059	Angstrom
C2  -2.9289	1.6876	0.5453	Angstrom
C4	-6.1305	-0.7681	-5.1015	Angstrom
C6	-4.8114	-1.235	-5.1747	Angstrom
C8	-3.8649	-0.9139	-4.2212	Angstrom
C10	-4.2929	-0.0952	-3.1672	Angstrom
C12 -2.6971	2.4078	1.7281	Angstrom
C14	-3.6824	3.1871	2.2912	Angstrom
C16	-4.9478	3.2648	1.7082	Angstrom
C18	-5.2128	2.5709	0.5516	Angstrom
C20	-4.2101	1.7851	-0.0575	Angstrom
C22	-4.5044	1.1143	-1.3041	Angstrom
C24	-5.611	0.3619	-3.0981	Angstrom
C25	-6.5601	0.0378	-4.059	Angstrom
End of Basis Set

Basis Set
Cl.ANO-RCC-MB.
Cl1	-1.0145	-2.1836	1.2415	Angstrom
Cl3	0.7002	0.9747	2.3666	Angstrom
Cl2	1.0145	2.1836	-1.2415	Angstrom
Cl4	-0.7002	-0.9747	-2.3666	Angstrom
End of Basis Set

Basis Set
Dy.ANO-RCC-MB.
Dy1	0	0	0	Angstrom
End of Basis Set

Basis Set
H.ANO-RCC-MB.
H1	6.4287	-1.5319	1.5909	Angstrom
H3	6.746	1.0091	5.7839	Angstrom
H5	4.5592	1.7917	5.9022	Angstrom
H7	2.9713	1.2295	4.2777	Angstrom
H9	1.8464	-2.356	-2.1468	Angstrom
H11	2.8197	-0.2291	1.8316	Angstrom
H13	3.4992	-3.6761	-3.0846	Angstrom
H15	5.6251	-3.797	-2.1101	Angstrom
H17	6.0765	-2.6201	-0.1602	Angstrom
H19	7.4553	-0.3514	4.0045	Angstrom
H2	-6.4287	1.5319	-1.5909	Angstrom
H4	-6.746	-1.0091	-5.7839	Angstrom
H6	-4.5592	-1.7917	-5.9022	Angstrom
H8	-2.9713	-1.2295	-4.2777	Angstrom
H10	-1.8464	2.356	2.1468	Angstrom
H12	-2.8197	0.2291	-1.8316	Angstrom
H14	-3.4992	3.6761	3.0846	Angstrom
H16	-5.6251	3.797	2.1101	Angstrom
H18	-6.0765	2.6201	0.1602	Angstrom
H20	-7.4553	0.3514	-4.0045	Angstrom
End of Basis set

Basis Set
N.ANO-RCC-MB.
N1	5.6947	-1.1119	1.9332	Angstrom
N3	3.6476	-0.3894	2.0452	Angstrom
N2	-5.6947	1.1119	-1.9332	Angstrom
N4	-3.6476	0.3894	-2.0452	Angstrom
End of Basis set

Basis Set
O.ANO-RCC-MB.
O1	1.9811	-0.9404	-0.0126	Angstrom
O2	-1.9811	0.9404	0.0126	Angstrom
End of Basis Set

&RASSCF
Title=Energy of quintuplet state
thrs= 1.0e-07 1.0e-04 1.0e-04
symmetry
1
CHOI
	DMPK
	0.0001
ENDC
CIMX
200
Spin
6
ciroot
21 21 1
Nactel
9 0 0
Inactive
173
Ras2
7
Iterations
200 100
levshift
1.5
SDAV
500
ORBL
ALL
ORBA
FULL

Last edited by Slowloris (2017-09-01 05:17:41)

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,011

Re: [SOLVED] RASSCF converge problem for a molecule with D2h symmetry

Have you checked the starting orbitals? It seems to me you are blindly picking the guessed orbitals from Seward, and trusting that orbitals 174-180 are a good active space. Is this so? (Also the "title" is wrong, if Spin=6 the state is a sextet, and note the molecule has a -1 charge.)

Slowloris

Member

Registered: 2017-09-01

Posts: 4

Re: [SOLVED] RASSCF converge problem for a molecule with D2h symmetry

Hi Ignacio,
Thank you so much for replying my naive question. The guess orbitals in active space is not good. Since I am trying to study the magnetic property of the metal center, I would like the active space to be the 4f orbitals of it. But now the orbitals seem to locate on ligands. So how should I adjust to obtain a better initial guess?

The title should be sextet, sorry about the confusion. And the molecule has -1 charge.

Last edited by Slowloris (2017-09-01 14:40:54)

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,011

Re: [SOLVED] RASSCF converge problem for a molecule with D2h symmetry

Use the ALTER keyword in &RASSCF to put the orbitals you want in the range 174-180. For instance, if the orbitals you want in the active space happen to be 160,169,176,177,178,194,207, the following should put them in the right place:

&RASSCF
Alter = 4
1 160 174
1 169 175
1 194 179
1 207 180

Or take your $Project.GssOrb file, open it in a text editor and at the end you have an #INDEX block. It is just a table where the first row and first column are headers to help you find the orbitals by number. The characters in the table indicate if an orbital is inactive (i), RAS2 (2) or secondary (s), so you should change it to something like:

#INDEX
* 1234567890
0 iiiiiiiiii
1 iiiiiiiiii
2 iiiiiiiiii
3 iiiiiiiiii
4 iiiiiiiiii
5 iiiiiiiiii
6 iiiiiiiiii
7 iiiiiiiiii
8 iiiiiiiiii
9 iiiiiiiiii
0 iiiiiiiiii
1 iiiiiiiiii
2 iiiiiiiiii
3 iiiiiiiiii
4 iiiiiiiiii
5 iiiiiiiii2
6 iiiiiiii2i
7 iii22222ss
8 ssssssssss
9 sss2ssssss
0 ssssss2sss
1 ssssssssss
2 ssssssssss
3 ssssssssss
4 ssssssssss
5 sssssssss

Then save this file with another name and use it with:

&RASSCF
FileOrb = /full/path/to/the/file

Slowloris

Member

Registered: 2017-09-01

Posts: 4

Re: [SOLVED] RASSCF converge problem for a molecule with D2h symmetry

Ignacio,

After altering, the new guess orbitals works at minimal basis set condition. Thank you very much, I learned a lot from this nice communication.

Yuanqi Zhai

Member

Registered: 2017-06-27

Posts: 15

Re: [SOLVED] RASSCF converge problem for a molecule with D2h symmetry

Hi,

It is a good example for me to learn how to calculate the Dy molecule, and I have learnt a lot about the set of RASSCF.

Then, I want to figure out the 27 Crystal-Field parameters using Single_aniso module and do not know how to do. Could you show me the basic formation?

Thanks in advance.

regards,
Zhai Yuanqi