CCL:G: Transition state for recombination of dibromomercury

 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"
 <owner-chemistry_._ccl.net>
 To: "Simón, Luis Manuel "
 <luissimonrubio_._hotmail.com>
 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]
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 >
 > 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 <mailto:hovell###cetem.gov.br>
 >
 >
 >
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 Transitional//EN">
 > <HTML><HEAD>
 > <META HTTP-EQUIV="Content-Type" CONTENT="text/html;
 charset=iso-8859-1">
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 name=GENERATOR></HEAD>
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 > <DIV><FONT face=Arial size=2><SPAN
 class=718415311-24022006>Dear
 > CCLers,</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 class=718415311-24022006>I am assuming
 a
 > linear transition state for the recombination of a bromine radical with
 the
 > bromomercury radical forming the dibromo
 molecule.</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 class=718415311-24022006>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.</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 class=718415311-24022006>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.</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 >
 class=718415311-24022006></SPAN></FONT>&nbsp;</DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 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?</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 class=718415311-24022006>All ideas
 would be
 > welcome and a summary will be posted if this post generates
 > interest.</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 > class=718415311-24022006>TIA</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 > class=718415311-24022006>Ian</SPAN></FONT></DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 >
 class=718415311-24022006></SPAN></FONT>&nbsp;</DIV>
 > <DIV><FONT face=Arial size=2><SPAN
 >
 class=718415311-24022006></SPAN></FONT>&nbsp;</DIV>
 > <DIV><FONT face=Arial size=2>Ian Hovell - Ph.D.
 <BR>NUCLEO DE MODELAGEM
 > MOLECULAR-NMM <BR>Centro de Tecnologia Mineral - CETEM
 <BR>Ministerio da
 Cincia
 > e da Tecnologia- MCT <BR>Avenida Ip, No 900 - Cidade Universitaria
 <BR>Ilha do
 > Fundo Rio de Janeiro RJ Brasil <BR>CEP 21941-590 <BR>tel 00 55
 (xx) 3865
 7344 ou
 > 3865 - 7216 <BR>Fax 00 55 (xx) 22602837 ou 2290-4286 <BR>e-mail
 <A
 > href="mailto:hovell###cetem.gov.br";>hovell###cetem.gov.br</A>
 <BR></FONT></DIV>
 > <DIV>&nbsp;</DIV></BODY></HTML>
 >
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