From owner-chemistry@ccl.net Thu Nov 28 05:55:01 2013 From: "Jens Spanget-Larsen spanget*o*ruc.dk" To: CCL Subject: CCL: eps(max) = 54365.8 * f ? Message-Id: <-49380-131128055300-17985-C7G1mouVDJFEnY6ldvvgjg-,-server.ccl.net> X-Original-From: Jens Spanget-Larsen Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_A94E15A372E6194CA8719D62642F67445E9BDAE7MBX1adrucdk_" Date: Thu, 28 Nov 2013 10:52:50 +0000 MIME-Version: 1.0 Sent to CCL by: Jens Spanget-Larsen [spanget,ruc.dk] --_000_A94E15A372E6194CA8719D62642F67445E9BDAE7MBX1adrucdk_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Dear CCL! The program CNDUV99 published in 1977 by H. Baumann (QCPE 333) for computat= ion of electronic transitions prints estimated log[epsilon] values based on= the relation eps(max) =3D 54365.8 * f, where f is the calculated oscillato= r strength. Can anyone tell me how the factor 54365.8 was derived? Yours, Jens >--< ------------------------------------------------------ JENS SPANGET-LARSEN Office: +45 4674 2710 Dept. of Science (18.1) 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 ------------------------------------------------------ --_000_A94E15A372E6194CA8719D62642F67445E9BDAE7MBX1adrucdk_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Dear CCL!

 

The program CNDUV99 published in 1977 by= H. Baumann (QCPE 333) for computation of electronic transitions prints est= imated log[epsilon] values based on the relation eps(max) =3D 54365.8 * f, where f is the calculated oscillator strength. C= an anyone tell me how the factor 54365.8 was derived?

 

Yours, Jens >--<=

 

  ---------------------------------= ---------------------

  JENS SPANGET-LARSEN  &n= bsp;      Office:      &#= 43;45 4674 2710

  Dept. of Science (18.1) &nbs= p;   Fax:         +45= 4674 3011

  Roskilde University  &n= bsp;      Mobile:      &#= 43;45 2320 6246

  P.O.Box 260   &nbs= p;             = E-Mail:     spanget _ ruc.dk

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

  ------------------------------------------------= ------

--_000_A94E15A372E6194CA8719D62642F67445E9BDAE7MBX1adrucdk_-- From owner-chemistry@ccl.net Thu Nov 28 09:02:00 2013 From: "Sergio Manzetti sergio.manzetti:gmx.com" To: CCL Subject: CCL:G: Earth metal oxides in Gaussian Message-Id: <-49381-131128080302-29528-AreCK9YjsV+Rt9KGX3AzSg*o*server.ccl.net> X-Original-From: "Sergio Manzetti" Date: Thu, 28 Nov 2013 08:03:01 -0500 Sent to CCL by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com] Dear all, as earth metal oxides, such as ZnO are particles, how can these be represented correctly as single molecules for calculations? Considering their charge, for instance, Mg2+ and O2-, their bonding should be ionic, however this is not clearly represented in the gaussian outputs when running simple MgO calculations and Mg can assimilate multiple bonds to other neighbouring atoms. How can this be correctly defined? Should open shell calculations be used? Thanks From owner-chemistry@ccl.net Thu Nov 28 19:11:00 2013 From: "Laurence Cuffe cuffe(~)mac.com" To: CCL Subject: CCL:G: Earth metal oxides in Gaussian Message-Id: <-49382-131128162917-32619-pnhNFH78MBahL8PQMyJ3aA**server.ccl.net> X-Original-From: Laurence Cuffe Content-type: multipart/alternative; boundary="Boundary_(ID_E/nAf71qODYgkBVyU/acgw)" Date: Thu, 28 Nov 2013 21:29:15 +0000 (GMT) MIME-version: 1.0 Sent to CCL by: Laurence Cuffe [cuffe-,-mac.com] --Boundary_(ID_E/nAf71qODYgkBVyU/acgw) Content-type: text/plain; charset=utf-8; format=flowed Content-transfer-encoding: quoted-printable Sent from QCloud On Nov 28, 2013, at 05:03 AM, "Sergio Manzetti sergio.manzetti:gmx.com" wrote: > > Sent to CCL by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com] > Dear all, as earth metal oxides, such as ZnO are particles, how can thes= e be represented correctly as single molecules for calculations? Consideri= ng their charge, for instance, Mg2+ and O2-, their bonding should be ionic= , however this is not clearly represented in the gaussian outputs when run= ning simple MgO calculations and Mg can assimilate multiple bonds to other= neighbouring atoms. > > How can this be correctly defined? Should open shell calculations be use= d? > > Thanks =20 There is a bit of a culture and language issue here. We are taught all sor= ts of models of bonding and electron behavior in our chemical education, a= nd it is sometimes dificult to realise that an electronic structure model,= as implemented by an ab initio program such as the one you mentioned, is = a deeper model where the language of interation which we inherit from the = simpler descriptions, may no longer be the most acurate way of describing = what is happening. By all means try open shell calculations, but be prepar= ed for the eventuality that they may not clarify the picture in terms of a= simpler understanding.=EF=BB=BF All the best Laurence Cuffe > > > > -=3D This is automatically added to each message by the mailing script =3D= -> > --Boundary_(ID_E/nAf71qODYgkBVyU/acgw) Content-type: multipart/related; boundary="Boundary_(ID_0X8C8W0hmuyv5TrjwP0rvQ)"; type="text/html" --Boundary_(ID_0X8C8W0hmuyv5TrjwP0rvQ) Content-type: text/html; CHARSET=US-ASCII Content-transfer-encoding: quoted-printable 

Sent from QCloud

On Nov 28, 2013, a= t 05:03 AM, "Sergio Manzetti sergio.manzetti:gmx.com" <owner-chemistry-,-= ccl.net> wrote:


Sent to CCL by: "Sergio Manzetti" [se= rgio.manzetti(a)gmx.com]
Dear all, as earth metal oxides, such as ZnO = are particles, how can these be represented correctly as single molecules = for calculations? Considering their charge, for instance, Mg2+ and O2-, th= eir bonding should be ionic, however this is not clearly represented in th= e gaussian outputs when running simple MgO calculations and Mg can assimil= ate multiple bonds to other neighbouring atoms.

How can this be = correctly defined? Should open shell calculations be used?

Thanks=
 
There is a bit of a c= ulture and language issue here. We are taught all sorts of models of bondi= ng and electron behavior in our chemical education, and it is sometimes di= ficult to realise that an electronic structure model, as implemented by an= ab initio program such as the one you mentioned, is a deeper model where = the language of interation which we inherit from the simpler descriptions,= may no longer be the most acurate way of describing what is happening. By= all means try open shell calculations, but be prepared for the eventualit= y that they may not clarify the picture in terms of a simpler understandin= g.
All the best
Laurence Cuffe


=



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