From owner-chemistry@ccl.net Fri Apr 20 09:23:00 2012 From: "Yavuz Dede dede:gazi.edu.tr" To: CCL Subject: CCL:G: Avoided crossing Message-Id: <-46742-120420045147-18621-kRDTSflb4EVQ/MGSGUOghA!A!server.ccl.net> X-Original-From: Yavuz Dede Content-Type: multipart/alternative; boundary="------------080205020204050601040106" Date: Fri, 20 Apr 2012 11:51:33 +0300 MIME-Version: 1.0 Sent to CCL by: Yavuz Dede [dede(a)gazi.edu.tr] This is a multi-part message in MIME format. --------------080205020204050601040106 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Dear Ibrahim, Most MCSCF software (MOLCAS, MOLPRO, GAMESS) calculates what you ask, between different space and/or spin states. For example in GAMESS-US these crossing searches are named minimum energy crossing (MEX). Note that, you wouldn't term it an avoided crossing from the beginning. Crossings between different states can be true intersections. Designation of conical intersection or avoided crossing requires a detailed analysis of the relative energies and electronic properties of the states under investigation. Reading works of Dupuis, Schlegel, Robb (among many others) may help. Best, Yavuz On 20.04.2012 02:36, Walid M. I. Hassan walid_m76.:.yahoo.com wrote: > Sent to CCL by: "Walid M. I. Hassan" [walid_m76|-|yahoo.com] > Dear Scientists > > long time since I send email via this list, > my question is very simple does anyone know a software to determine the > avoided crossing or conical intersection between singlet and triplet states, > i mean states of different multiplicity > > In Gaussian 09 manual, in Opt keyword ,under conical option it is written, > "Search for a conical intersection or avoided crossing using the state- > averaged CASSCF method. Avoided is a synonym for Conical. Note that > CASSCF=SlaterDet is needed in order to locate a conical intersection between > a singlet state and a triplet state." > I tried this and find it is impossible since in input file you determine a > singlet or triplet multiplicity but not both > > and SlaterDet option just reverse the spin but do not change multiplicity > see this part of output to see the configurations > > when I use singlet state with No SLATER DETERMINANT >> I get the following configuration >> Configuration 1 Symmetry 1 111000 >> Configuration 2 Symmetry 1 11ab00 >> Configuration 3 Symmetry 1 110100 >> Configuration 4 Symmetry 1 1a1b00 >> >> >> which become as follows with SLATER DETERMINANT >> Configuration 1 Symmetry 1 111000 >> Configuration 2 Symmetry 1 11ba00 >> Configuration 3 Symmetry 1 11ab00 >> Configuration 4 Symmetry 1 1b1a00 >> Configuration 5 Symmetry 1 11b0a0 >> >> >> for triplet state in both cases i get the following configuration >> Configuration 1 Symmetry 1 11aa00 >> Configuration 2 Symmetry 1 11a0a0 >> Configuration 3 Symmetry 1 1a1a00 >> Configuration 4 Symmetry 1 110aa0 > as you can see SlaterDet option reverse ab to ba but not to aa > I want to get conical intersection or avoided crossing between > Configuration 1 Symmetry 1 111000 of singlet and > Configuration 1 Symmetry 1 11aa00 of triplet state > > I sent this question to Gaussian team and their reply was not convincing to > me, I will put it here for your reference, > I think they just go around the problem to claim that there is no problem in > the manual > i think gaussian program can not do it > if i am wrong i will appreciate if you guide me > If i am write so what program can find this conical intersection for me > sorry for long email but i think it won't show my point if it is shorter > > Dr. Ibrahim, > > Thank you for giving us a chance to comment. > > When you look at those configuration lists you are not actually > looking a lists of identical things. The singlet without Slater Determinant > is a list of configurations, fixed linear combinations of determinants > giving singlets. So there will be no triplet terms in this expansion > and the higher roots of the CASSCF equations will all be singlets as > well. > > The second case lists determinants directly and generates singlets > and m(l)=0 triplets. So configurations 2 and 3 are a pair of determinants > which can contribute to both singlets and triplets with the sign difference > carried on the CI expansion coefficients, not on the determinants > directly. > > The third case correspond to a ground state triplet, m(l)=+/-1 > and no singlet contributions are possible. Again any excited states will > be triplets so this reference is not suitable for the crossing. > > So the program can compute the crossing you desire by using a > singlet reference with SlaterDet included in the option list. You > should still solve for the first few roots to confirm that you have > the second root corresponding to the triplet you expected.> > > > -- > ||||||||||||||||||||||| > Yavuz Dede > GÜ-Fen Fakültesi > Kimya Bölümü > L-128 06500 Ankara > Tel: 312-202-1386 > Faks: 312-212-2279 > |||||||||||||||||||| > Yavuz Dede, Ph.D. > Theoretical/Computational Chemistry > Gazi University > Faculty of Science > Department of Chemistry > 06500 Ankara TURKEY > http://w3.gazi.edu.tr/~dede/ydd.htm > |||||||||||||||||||||||||||||||||||| --------------080205020204050601040106 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Dear Ibrahim,
Most MCSCF software (MOLCAS, MOLPRO, GAMESS) calculates what you ask, between different space and/or spin states. For example in GAMESS-US these crossing searches are named minimum energy crossing (MEX).

Note that, you wouldn't term it an avoided crossing from the beginning. Crossings between different states can be true intersections. Designation of conical intersection or avoided crossing requires a detailed analysis of the relative energies and electronic properties of the states under investigation.

Reading works of Dupuis, Schlegel, Robb (among many others) may help.

Best,
Yavuz



On 20.04.2012 02:36, Walid M. I. Hassan walid_m76.:.yahoo.com wrote: 
Sent to CCL by: "Walid M. I. Hassan" [walid_m76|-|yahoo.com]
Dear Scientists

long time since I send email via this list,
my question is very simple does anyone know a software to determine the 
avoided crossing or conical intersection between singlet and triplet states, 
i mean states of different multiplicity

In Gaussian 09 manual, in Opt keyword ,under conical option it is written, 
"Search for a conical intersection or avoided crossing using the state-
averaged CASSCF method. Avoided is a synonym for Conical. Note that 
CASSCF=SlaterDet is needed in order to locate a conical intersection between 
a singlet state and a triplet state." 
I tried this and find it is impossible since in input file you determine a 
singlet or triplet multiplicity but not both

and SlaterDet option just reverse the spin but do not change multiplicity
see this part of output to see the configurations

when I use singlet state with No SLATER DETERMINANT

I get the following configuration
       Configuration      1 Symmetry 1 111000
       Configuration      2 Symmetry 1 11ab00
       Configuration      3 Symmetry 1 110100
       Configuration      4 Symmetry 1 1a1b00


which become as follows with SLATER DETERMINANT
       Configuration      1 Symmetry 1 111000
       Configuration      2 Symmetry 1 11ba00
       Configuration      3 Symmetry 1 11ab00
       Configuration      4 Symmetry 1 1b1a00
       Configuration      5 Symmetry 1 11b0a0


for triplet state in both cases i get the following configuration
 Configuration      1 Symmetry 1 11aa00
       Configuration      2 Symmetry 1 11a0a0
       Configuration      3 Symmetry 1 1a1a00
       Configuration      4 Symmetry 1 110aa0

as you can see SlaterDet option reverse ab to ba but not to aa
I want to get conical intersection or avoided crossing between
Configuration      1 Symmetry 1 111000 of singlet and
Configuration      1 Symmetry 1 11aa00 of triplet state

I sent this question to Gaussian team and their reply was not convincing to 
me, I will put it here for your reference,
I think they just go around the problem to claim that there is no problem in 
the manual
i think gaussian program can not do it
if i am wrong i will appreciate if you guide me
If i am write so what program can find this conical intersection for me
sorry for long email but i think it won't show my point if it is shorter 

   Dr. Ibrahim,

    Thank you for giving us a chance to comment.

    When you look at those configuration lists you are not actually
looking a lists of identical things.  The singlet without Slater Determinant
is a list of configurations, fixed linear combinations of determinants
giving singlets.  So there will be no triplet terms in this expansion
and the higher roots of the CASSCF equations will all be singlets as
well.

    The second case lists determinants directly and generates singlets
and m(l)=0 triplets.  So configurations 2 and 3 are a pair of determinants
which can contribute to both singlets and triplets with the sign difference
carried on the CI expansion coefficients, not on the determinants
directly.

      The third case correspond to a ground state triplet, m(l)=+/-1 
and no singlet contributions are possible.  Again any excited states will
be triplets so this reference is not suitable for the crossing.

      So the program can compute the crossing you desire by using a 
singlet reference with SlaterDet included in the option list.  You
should still solve for the first few roots to confirm that you have
the second root corresponding to the triplet you expected.E-mail to subscribers: CHEMISTRY[-]ccl.net or use:
      http://www.ccl.net/cgi-bin/ccl/send_ccl_message

E-mail to administrators: CHEMISTRY-REQUEST[-]ccl.net or use
      http://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtml

Before posting, check wait time at: http://www.ccl.net

Job: http://www.ccl.net/jobs 
Conferences: http://server.ccl.net/chemistry/announcements/conferences/

Search Messages: http://www.ccl.net/chemistry/searchccl/index.shtmlhttp://www.ccl.net/spammers.txt

RTFI: http://www.ccl.net/chemistry/aboutccl/instructions/



-- 
|||||||||||||||||||||||
Yavuz Dede
GÜ-Fen Fakültesi
Kimya Bölümü
L-128 06500 Ankara
Tel:  312-202-1386
Faks: 312-212-2279
||||||||||||||||||||
Yavuz Dede, Ph.D.
Theoretical/Computational Chemistry
Gazi University
Faculty of Science
Department of Chemistry
06500 Ankara TURKEY
http://w3.gazi.edu.tr/~dede/ydd.htm
||||||||||||||||||||||||||||||||||||
--------------080205020204050601040106--