From owner-chemistry@ccl.net Mon Oct 18 08:53:01 2021 From: "Sumangla Arora arorasumangla]^[gmail.com" To: CCL Subject: CCL: Transition state having more than one imaginary mode Message-Id: <-54478-211018021354-17534-yOKo9hHDmiGySfoE5RpwRQ]=[server.ccl.net> X-Original-From: Sumangla Arora Content-Type: multipart/alternative; boundary="000000000000a59e5905ce9a728e" Date: Mon, 18 Oct 2021 11:45:22 +0530 MIME-Version: 1.0 Sent to CCL by: Sumangla Arora [arorasumangla%x%gmail.com] --000000000000a59e5905ce9a728e Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Thank you! If I got you right, I have run the scan along with the normal mode and got the connected intermediates (as you suggested) which shows that the TS is right. So the next question is, do I need to search TS again from these intermediates, or what do I have to do next to remove the other imaginary modes? I didn't get it properly. I have used ORCA 4.2.1 software for the transition state determination. I have done the calculation using default SCF (TightSCF) and default grid (2). Best Regards Sumangla On Sat, Oct 16, 2021 at 3:11 PM Marcel Swart (GMail) marcel.swart**gmail.co= m wrote: > Indeed, the first thing is to distort along the 400i mode, and reoptimize= . > Normally that should go to the new structure where it is gone. > if not, then depending on the software you use you might be able to do a > scan along the normal mode, which recomputes the frequency value. > Often this shows that the imaginary value is spurious and in reality it i= s > positive. > If you cannot do that, then try computing the frequency with larger grid. > > Sent to CCL by: "SUMANGLA ARORA" [arorasumangla*_*gmail.com] > Dear All, > I am getting three imaginary modes in a transition state viz., i1300, > i400, > i50. Out of them, i1300 is the correct one which has the vibrational mode > we > were expecting. How can we eliminate the other imaginary modes?. I have > tried > to eradicate the i400 imaginary mode by taking the geometry on both ends > of the > vibrational mode (i400), but this is not working. > > > Thanks > > > > *Marcel Swart* > ICREA Research Professor at University of Girona > Director of Institut de Qu=C3=ADmica Computacional i Cat=C3=A0lisi > > Univ. Girona, Campus Montilivi (Ci=C3=A8ncies) > c/ M.A. Capmany 69 > 17003 Girona, Spain > > www.marcelswart.eu > marcel.swart**gmail.com > > vCard > addressbook://www.marcelswart.eu/MSwart.vcf > > --000000000000a59e5905ce9a728e Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Thank you!
If I got you right, I have run the scan alon= g with the normal mode and got the connected intermediates (as you suggeste= d) which shows that the TS is right. So the next question is, do I need to = search TS again from these intermediates, or what do I have to do next to r= emove the other imaginary modes? I didn't get it properly.

I hav= e used ORCA 4.2.1 software for the transition state determination. I have d= one the calculation using default SCF (TightSCF) and default grid (2).=C2= =A0

Best Regards
Sumangla

<= div class=3D"gmail_quote">
On Sat, Oct= 16, 2021 at 3:11 PM Marcel Swart (GMail) marcel.swart**gmail.com <owne= r-chemistry%ccl.net> wrote:
Indeed, the fi= rst thing is to distort along the 400i mode, and reoptimize. Normally that = should go to the new structure where it is gone.
if not, then depending= on the software you use you might be able to do a scan along the normal mo= de, which recomputes the frequency value.
Often this shows that t= he imaginary value is spurious and in reality it is positive.
If = you cannot do that, then try computing the frequency with larger grid.

Sent to CCL by: "SUMANGL= A =C2=A0ARORA" [arorasumangla*_*gmail.com]
Dear All,
I am getting three imag= inary modes in a transition state viz., i1300, i400,
i50. Out of them, = i1300 is the correct one which has the vibrational mode we
were expecti= ng. How can we eliminate the other imaginary modes?. I have tried
to er= adicate the i400 imaginary mode by taking the geometry on both ends of the =
vibrational mode (i400), but this is not working.


Thanks
=


Marcel=C2=A0Swart
ICREA Research Professor at University of Gi= rona
Direc= tor of Institut de Qu=C3=ADmica Computacional i=C2=A0Cat=C3=A0lisi

<= div style=3D"color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-sty= le:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text= -transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><= font style=3D"background-color:rgba(255,255,255,0)">Univ. Girona, Campus Mo= ntilivi (Ci=C3=A8ncies)
c/ M.A. Ca= pmany 69
17003 Girona, Spain


vCard

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