From owner-chemistry@ccl.net Sat Oct 16 02:01:00 2021 From: "SUMANGLA ARORA arorasumangla- -gmail.com" To: CCL Subject: CCL: Transition state having more than one imaginary mode Message-Id: <-54475-211015024446-301-VQuVDNvbAkjrLb6/gfNpGA|server.ccl.net> X-Original-From: "SUMANGLA ARORA" Date: Fri, 15 Oct 2021 02:44:44 -0400 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 From owner-chemistry@ccl.net Sat Oct 16 03:17:01 2021 From: "Marcel Swart (GMail) marcel.swart**gmail.com" To: CCL Subject: CCL: Transition state having more than one imaginary mode Message-Id: <-54476-211016031543-18090-4FCZf+o18et87gL/qlDHkQ+*+server.ccl.net> X-Original-From: "Marcel Swart (GMail)" Content-Type: multipart/alternative; boundary="Apple-Mail=_6FAC0DDA-9DD5-4D69-B301-5790B8BDDE9B" Date: Sat, 16 Oct 2021 09:15:30 +0200 Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.7\)) Sent to CCL by: "Marcel Swart (GMail)" [marcel.swart#%#gmail.com] --Apple-Mail=_6FAC0DDA-9DD5-4D69-B301-5790B8BDDE9B Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 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 = 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,=20 > i50. Out of them, i1300 is the correct one which has the vibrational = mode we=20 > were expecting. How can we eliminate the other imaginary modes?. I = have tried=20 > to eradicate the i400 imaginary mode by taking the geometry on both = ends of the=20 > vibrational mode (i400), but this is not working. >=20 >=20 > 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 = --Apple-Mail=_6FAC0DDA-9DD5-4D69-B301-5790B8BDDE9B Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 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 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 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

= --Apple-Mail=_6FAC0DDA-9DD5-4D69-B301-5790B8BDDE9B--