From owner-chemistry %-% at %-% ccl.net Thu Dec 13 09:30:01 2018 From: "Satyajit D.B. satyadey100-.-gmail.com" To: CCL Subject: CCL: adsorption energies Message-Id: <-53568-181213092813-32356-0nP9AmfAMKI8wk7yQ1DayA+/-server.ccl.net> X-Original-From: "Satyajit D.B." Content-Type: multipart/alternative; boundary="00000000000090398c057ce81f0e" Date: Thu, 13 Dec 2018 19:57:58 +0530 MIME-Version: 1.0 Sent to CCL by: "Satyajit D.B." [satyadey100[#]gmail.com] --00000000000090398c057ce81f0e Content-Type: text/plain; charset="UTF-8" Hi Anyao, I think the adsorption energies is given by the following equation- Eads = E1-2-(E1 + E2). And reverse is for Binding energies - Eb = E1 + E2 - E1-2. And more positive the binding energies, more stable the structure will be. For thermochemical calculations(whether exothermic or endothermic), you should use enthalpy values and for determing the spontaneity you should opt for free energy values which may be also used for calculating the barrier involved in the reaction mechanism to construct an energy profile diagram for the complete pathway. Hope this helps. Best regards, Satyajit On Thu, Dec 13, 2018 at 7:37 PM anyao jiao 1425623121[-]qq.com < owner-chemistry===ccl.net> wrote: > > Sent to CCL by: "anyao jiao" [1425623121||qq.com] > Hi everyone. > I have some questions about adsorption energies.Some paper reported > that the > adsorption energies (Eads) of 1-2 systems were obtained as: Eads = E1 + E2 > - E1-2, > and the more positive the values of Eads, the more stable the adsorbed > structures. > Others said that Eads = E1-2-(E1 + E2). So which one is right? By the way, > which > energy should I use, Enthalpies or Free Energies? > Looking forward to your reply.Thank you.> > > -- Satyajit Dey Baruah Research Scholar, Department of Chemical Sciences, Tezpur University,Napaam,Tezpur PIN-784001, Mob:+919401341691 --00000000000090398c057ce81f0e Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi Anyao,

I thin= k the adsorption energies is given by the following equation-=C2=A0E= ads =3D E1-2-(E1 + E2).=C2=A0
And reverse is for Binding energies= - Eb =3D E1 + E2 - E1-2. And more positive the binding energies, more stab= le the structure will be.

For thermochemical calcu= lations(whether exothermic or endothermic), you should use enthalpy values = and for determing the spontaneity you should opt for free energy values whi= ch may be also used for calculating the barrier involved in the reaction me= chanism to construct an energy profile diagram for the complete pathway.=C2= =A0

Hope this helps.

Best= regards,
Satyajit

On Thu, Dec 13, 2018 at 7:37 PM anyao jiao 1425623121[-]qq.com <owner-chemistry===ccl.net> wrote:

Sent to CCL by: "anyao=C2=A0 jiao" [1425623121||qq.com]
Hi everyone.
=C2=A0 =C2=A0I have some questions about adsorption energies.Some paper rep= orted that the
adsorption energies (Eads) of 1-2 systems were obtained as: Eads =3D E1 + E= 2 - E1-2,
and the more positive the values of Eads, the more stable the adsorbed stru= ctures.=C2=A0
Others said that Eads =3D E1-2-(E1 + E2). So which one is right? By the way= , which
energy should I use, Enthalpies or Free Energies?
=C2=A0 =C2=A0Looking forward to your reply.Thank you.



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--
Satyajit Dey Baruah
Researc= h Scholar,
Department of Chemical Sciences,
Tezpur Univ= ersity,Napaam,Tezpur
PIN-784001,
Mob:+919401341691
--00000000000090398c057ce81f0e--