From owner-chemistry -8 at 8- ccl.net Mon Sep 28 11:46:01 2015 From: "Fredrick Mutunga fredrick.mutunga(0)gmail.com" To: CCL Subject: CCL: SV: Fitting IRC data to a polynomial function Message-Id: <-51784-150928114323-24790-iM9bJ+Tcx8fz3SgFPJj/4A%a%server.ccl.net> X-Original-From: Fredrick Mutunga Content-Type: multipart/alternative; boundary=001a113eca2e4e94e60520d08ee5 Date: Mon, 28 Sep 2015 09:43:16 -0600 MIME-Version: 1.0 Sent to CCL by: Fredrick Mutunga [fredrick.mutunga*_*gmail.com] --001a113eca2e4e94e60520d08ee5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Dear Jens, It looks like asymmetric double minimum. I have tried to fit it to a simple quartic potential but the fit isn't good. Thanks, Fred On Mon, Sep 28, 2015 at 2:12 AM, Jens Spanget-Larsen spanget _ ruc.dk < owner-chemistry]~[ccl.net> wrote: > Dear Fred; > > > > If your are investigating a symmetrical double minimum potential, you may > consider a simple quartic potential with a quadratic barrier. The numeric= al > solutions to the eigenvalue problem have been tabulated by Jaan Laane: > > > > http://dx.doi.org/10.13140/RG.2.1.3994.4161 > > > > Mvh, Jens >--< > > > > ------------------------------------------------------ > > JENS SPANGET-LARSEN Office: +45 4674 2710 > > Dept. of Science Fax: +45 4674 3011 > > Roskilde University Mobile: +45 2320 6246 > > P.O.Box 260 E-Mail: spanget * ruc.dk > > DK-4000 Roskilde, Denmark http://www.ruc.dk/~spanget > > ------------------------------------------------------ > > > ------------------------------ > *Fra:* owner-chemistry+spanget=3D=3Druc.dk * ccl.net > [owner-chemistry+spanget=3D=3Druc.dk * ccl.net] p=C3=A5 vegne af Fredrick= Mutunga > fredrick.mutunga..gmail.com [owner-chemistry * ccl.net] > *Sendt:* 28. september 2015 01:49 > *Til:* Jens Spanget-Larsen > *Emne:* CCL: Fitting IRC data to a polynomial function > > Hello Fellow CCL Members, > > I want to fit an IRC data points attached to a polynomial form to get a p= otential function which I intent to use in calculating WKB barrier penetrat= ion integral. I have tried several simple polynomials forms up to 5th order= including some exponentials using Mathematica's NonLinearModelFit but non = of them seem to work! > Does any of you guys have an idea what kind of form I should be trying? > > Thanks > > Fred > > --001a113eca2e4e94e60520d08ee5 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Dear Jens,

It looks like=C2=A0 asym= metric=C2=A0 double minimum. I have tried to fit it to a simple quartic=C2= =A0 potential but the fit isn't good.

Thanks,

=
Fred

On Mon, Sep 28, 2015 at 2:12 AM, Jens Spanget-Larsen spanget _ ruc.dk <owner-chemistry]~[ccl.net> wrote:

Dear Fred;

=C2=A0

If your are investigating a symmetrical double minimum potential, you ma= y consider a simple quartic potential with a quadratic barrier. The numeric= al solutions to the eigenvalue problem have been tabulated by Jaan Laane:

=C2=A0

http://dx.doi.org/10.13140/RG.2.1.3994.4161

=C2=A0

Mvh, Jens >--<

=C2=A0

=C2=A0 --------------= ----------------------------------------

=C2=A0 JENS SPANGET-LARSEN=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Office:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 +45 4= 674 2710

=C2=A0 Dept. of Science=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Fax:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 +45 4674 3011

=C2=A0 Roskilde University=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Mobile:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 +45 2= 320 6246

=C2=A0 P.O.Box 260=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 E-Mai= l:=C2=A0=C2=A0=C2=A0=C2=A0 spanget * ruc.dk

=C2=A0 DK-4000 Roskilde, Denmark=C2=A0=C2=A0 = http://www.ruc.dk/~spanget

=C2=A0 --------------------------------------= ----------------

=C2=A0

Fra: owner-chemistry+spanget=3D=3Druc.dk * = ccl.net [owner-chemistry+spanget=3D=3Druc.dk * ccl.n= et] p=C3=A5 vegne af Fredrick Mutunga fredrick.mutunga..gmail.com [owner-chemistry * ccl.net]
Sendt: 28. september 2015 01:49
Til: Jens Spanget-Larsen
Emne: CCL: Fitting IRC data to a polynomial function

Hello  Fellow CCL Members,

I want to fit an IRC data points attached to a polynomial form to get a pot=
ential function which I intent to use in calculating WKB barrier penetratio=
n integral. I have tried several simple polynomials forms up to 5th order i=
ncluding some exponentials using Mathematica's NonLinearModelFit but no=
n of them seem to work!
Does any of you guys have an idea what kind of form I should be trying?

Thanks

Fred

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