From owner-chemistry@ccl.net Fri Oct 22 12:08:01 2021 From: "Sumangla Arora arorasumangla : gmail.com" To: CCL Subject: CCL: Transition state having more than one imaginary mode Message-Id: <-54480-211022043954-18788-gjqMOgaRraCQbQEXF0K9MA,+,server.ccl.net> X-Original-From: Sumangla Arora Content-Type: multipart/alternative; boundary="0000000000000cbafa05ceecf4de" Date: Fri, 22 Oct 2021 14:11:25 +0530 MIME-Version: 1.0 Sent to CCL by: Sumangla Arora [arorasumangla^^^gmail.com] --0000000000000cbafa05ceecf4de Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Thank you Prof. Swart for your valuable support. I am glad to inform you that I got the right transition state with one imaginary mode. Thanks again Sumangla On Mon, Oct 18, 2021 at 8:16 PM Marcel Swart (GMail) wrote: > No, what I meant was: > distort along the 400i mode, and refind the TS. I=E2=80=99m sorry, my lan= guage was > confusing indeed. > > MS > > On 18 Oct 2021, at 08:15, Sumangla Arora arorasumangla]^[gmail.com < > owner-chemistry++ccl.net> wrote: > > Thank you! > If I got you right, I have run the scan along with the normal mode and go= t > 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.com 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 gon= e. >> 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 >> is 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 mod= e >> 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 >> >> > > *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 > > --0000000000000cbafa05ceecf4de Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Thank you Prof. Swart for your valuable support. I am glad= to inform you that I got the right transition state with one imaginary mod= e.
Thanks again
Sumangla

On Mon, Oct 18, 2021 at 8:16 PM= Marcel Swart (GMail) <marcel.swart++gmail.com> wrote:
No, what I meant was:
distort al= ong the 400i mode, and refind the TS. I=E2=80=99m sorry, my language was co= nfusing indeed.

MS

On 18 Oct 2021, at 08:15, Sumangla Arora arorasumangla]^[gmail.com <owner-chemistry++ccl.net>= ; wrote:

Thank you!
If I got you right, I= have run the scan along with the normal mode and got the connected interme= diates (as you suggested) which shows that the TS is right. So the next que= stion 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).=C2=A0

Best Regards
Suma= ngla

On Sat, Oct 16, 2021 at 3:11 PM Marcel Swart (GMail) marcel.swart= **gmail.com <owner-chemistry:+:c= cl.net> wrote:
Indeed, the first thing is to distort along the 400i mode, and r= eoptimize. 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 frequen= cy with larger grid.

Sent= to CCL by: "SUMANGLA =C2=A0ARORA" [arorasumangla*_*gmail.com]
Dear All,<= br>I am getting three imaginary modes in a transition state viz., i1300, i4= 00,
i50. Out of them, i1300 is the correct one which has the vibrationa= l mode we
were expecting. How can we eliminate the other imaginary mode= s?. I have tried
to eradicate the i400 imaginary mode by taking the geo= metry on both ends of the
vibrational mode (i400), but this is not work= ing.


Thanks


Marcel= =C2=A0Swart
ICREA Research Profe= ssor at University of Girona
Directo= r of Institut de Qu=C3=ADmica Computacional i=C2=A0Cat=C3=A0lisi

Un= iv. Girona, Campus Montilivi (Ci=C3=A8ncies)
c/ M.A. Capmany 69
17003 Girona, Spain


vCard



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
<= /div>

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