From owner-chemistry@ccl.net Sat Feb 25 11:48:00 2006 From: "luis simon luissimonrubio=-=hotmail.com" To: CCL Subject: CCL:G: Transition state for recombination of dibromomercury Message-Id: <-31001-060224164905-9270-d13bc3mUg8HuskBwXZnnXQ]|[server.ccl.net> X-Original-From: "luis simon" Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="iso-8859-1" Date: Fri, 24 Feb 2006 22:02:02 +0100 MIME-Version: 1.0 Sent to CCL by: "luis simon" [luissimonrubio|a|hotmail.com] Which is the multiplicity in your input file? I suggest that you try multiplicity 3 instead of 1 for the dirradical TS structure (if you did not do it before). I do not know why, but it worked for me in a very different reaction. Regards: Luis ----- Original Message ----- > From: "Ian Hovell HOVELL]|[cetem.gov.br" To: "Simón, Luis Manuel " Sent: Friday, February 24, 2006 9:12 PM Subject: CCL:G: Transition state for recombination of dibromomercury > Sent to CCL by: Ian Hovell [HOVELL/./cetem.gov.br] > This message is in MIME format. Since your mail reader does not understand > this format, some or all of this message may not be legible. > > ------_=_NextPart_001_01C6393D.C86E54E0 > Content-Type: text/plain; > charset="iso-8859-1" > > Dear CCLers, > I am assuming a linear transition state for the recombination of a bromine > radical with the bromomercury radical forming the dibromo molecule. > According to Nikolai (J Phys. Chem. A 2005, 109, 8765-8773) the two bond > lengths are 2.539 and 4.567 angstroms produced a transition state calculated > using CI methods. > I am trying to produce, without much success, a transition state for this > recombination reaction at the mpw1pw91 DFT level. In either full or partial > (where only one bond is relaxed) optimisations, the radicals either join > forming the dibromo molecule, and hence no imaginary frequency, or separate > completly according to the starting bond lengths. > > I am using the built in SDD basis set and G03w. The output produces a > warning that the bromine might be hypervalent but has no d functions - could > this be the problem or this this level of calculation just not up to finding > the transition state for this system? > All ideas would be welcome and a summary will be posted if this post > generates interest. > TIA > Ian > > > Ian Hovell - Ph.D. > NUCLEO DE MODELAGEM MOLECULAR-NMM > Centro de Tecnologia Mineral - CETEM > Ministerio da Cincia e da Tecnologia- MCT > Avenida Ip, No 900 - Cidade Universitaria > Ilha do Fundo Rio de Janeiro RJ Brasil > CEP 21941-590 > tel 00 55 (xx) 3865 7344 ou 3865 - 7216 > Fax 00 55 (xx) 22602837 ou 2290-4286 > e-mail hovell###cetem.gov.br > > > > ------_=_NextPart_001_01C6393D.C86E54E0 > Content-Type: text/html; > charset="iso-8859-1" > > > > > > > > >
Dear > CCLers,
>
I am assuming a > linear transition state for the recombination of a bromine radical with the > bromomercury radical forming the dibromo molecule.
>
According to Nikolai > (J Phys. Chem. A 2005, 109, 8765-8773) the two bond lengths are 2.539 and 4.567 > angstroms produced a transition state calculated using CI > methods.
>
I am trying to > produce, without much success, a transition state for this recombination > reaction at the mpw1pw91 DFT level. In either full or partial (where only one > bond is relaxed) optimisations, the radicals either join forming the dibromo > molecule, and hence no imaginary frequency, or separate completly according to > the starting bond lengths.
>
class=718415311-24022006> 
>
I am using the built > in SDD basis set and G03w. The output produces a warning that the bromine might > be hypervalent but has no d functions - could this be the problem or this this > level of calculation just not up to finding the transition state for this > system?
>
All ideas would be > welcome and a summary will be posted if this post generates > interest.
>
class=718415311-24022006>TIA
>
class=718415311-24022006>Ian
>
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>
class=718415311-24022006> 
>
Ian Hovell - Ph.D.
NUCLEO DE MODELAGEM > MOLECULAR-NMM
Centro de Tecnologia Mineral - CETEM
Ministerio da Cincia > e da Tecnologia- MCT
Avenida Ip, No 900 - Cidade Universitaria
Ilha do > Fundo Rio de Janeiro RJ Brasil
CEP 21941-590
tel 00 55 (xx) 3865 7344 ou > 3865 - 7216
Fax 00 55 (xx) 22602837 ou 2290-4286
e-mail href="mailto:hovell###cetem.gov.br">hovell###cetem.gov.br
>
 
> > ------_=_NextPart_001_01C6393D.C86E54E0--> > > >