From owner-chemistry@ccl.net Fri Apr 8 01:48:01 2016 From: "Rina Dao rina.dao!^!gmail.com" To: CCL Subject: CCL: How to identify fluorescence by quantum calculation? Message-Id: <-52130-160408014309-12222-YaPvwcgYUwnO96o2pdInLA|a|server.ccl.net> X-Original-From: Rina Dao Content-Type: multipart/alternative; boundary=001a11442b8e2273fc052ff2ab51 Date: Fri, 8 Apr 2016 15:43:03 +1000 MIME-Version: 1.0 Sent to CCL by: Rina Dao [rina.dao\a/gmail.com] --001a11442b8e2273fc052ff2ab51 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Dear colleges, For a fluorescent molecule, the emission =CE=BB can be calculated by TDDFT.= But how can I tell from a calculation that a molecule is not fluorescent ? For non-fluorescent molecule, the standard calculation can also yield an emission wavelength, right ? Then how can I identify whether a molecule is fluorescent by calculation ? Is it possible only by experiment ? I am trying to explain a fluorescence quenching experiment which seems to be static quenching (the fluorescent molecule and the quencher forms a ground state complex which is does not glow). How can I give prove to this mechanism ? What property should I calculate ? thanks in advance~ Rina --001a11442b8e2273fc052ff2ab51 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Dear colleges,

For a fluorescent mo= lecule, the emission =CE=BB can be calculated=20 by TDDFT. But how can I tell from a calculation that a molecule is not fluo= rescent ? For non-fluorescent molecule, the standard calculation can also yield an emission wavelength, right ? Then how can I identify=20 whether a molecule is fluorescent by calculation ? Is it possible only=20 by experiment ? I am trying to explain a fluorescence quenching=20 experiment which seems to be static quenching (the fluorescent molecule and the quencher forms a ground state complex which is does not glow).=20 How can I give prove to this mechanism ? What property should I=20 calculate ?

thanks in advance~

R= ina
--001a11442b8e2273fc052ff2ab51-- From owner-chemistry@ccl.net Fri Apr 8 10:30:01 2016 From: "=?UTF-8?Q?Andr=C3=A9_Farias_de_Moura?= moura(a)ufscar.br" To: CCL Subject: CCL: How to identify fluorescence by quantum calculation? Message-Id: <-52131-160408101657-24775-UP1pVvE8MvjmwdYTJ91/VQ[A]server.ccl.net> X-Original-From: =?UTF-8?Q?Andr=C3=A9_Farias_de_Moura?= Content-Type: multipart/alternative; boundary=001a113d516098a139052ff9d82e Date: Fri, 8 Apr 2016 11:16:50 -0300 MIME-Version: 1.0 Sent to CCL by: =?UTF-8?Q?Andr=C3=A9_Farias_de_Moura?= [moura**ufscar.br] --001a113d516098a139052ff9d82e Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Rina, I only do that for teaching purposes, but It seems to me that you cannot get that information from geometry optimization alone, you'll most likely get an emission spectra from the excited states optimized geometries. I'd suggest you to take a look at the papers by Gerrit Groenhof on the QM/MM molecular dynamics of excited states, which allow the excited states to find non-radiative paths back to the ground state along QM/MM MD simulations. I hope it helps Andre On Fri, Apr 8, 2016 at 2:43 AM, Rina Dao rina.dao!^!gmail.com < owner-chemistry=ccl.net> wrote: > Dear colleges, > > For a fluorescent molecule, the emission =CE=BB can be calculated by TDDF= T. But > how can I tell from a calculation that a molecule is not fluorescent ? Fo= r > non-fluorescent molecule, the standard calculation can also yield an > emission wavelength, right ? Then how can I identify whether a molecule i= s > fluorescent by calculation ? Is it possible only by experiment ? I am > trying to explain a fluorescence quenching experiment which seems to be > static quenching (the fluorescent molecule and the quencher forms a groun= d > state complex which is does not glow). How can I give prove to this > mechanism ? What property should I calculate ? > > thanks in advance~ > > Rina > --=20 _____________ Prof. Dr. Andr=C3=A9 Farias de Moura Department of Chemistry Federal University of S=C3=A3o Carlos S=C3=A3o Carlos - Brazil phone: +55-16-3351-8090 --001a113d516098a139052ff9d82e Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi Rina,

I only do that for te= aching purposes, but It seems to me that you cannot get that information fr= om geometry optimization alone, you'll most likely get an emission spec= tra from the excited states optimized geometries. I'd suggest you to ta= ke a look at the papers by Gerrit Groenhof on the QM/MM molecular dynamics= of excited states, which allow the excited states to find non-radiative pa= ths back to the ground state along QM/MM MD simulations.

I hop= e it helps

Andre

On Fri, Apr 8, 2016 at 2:43 AM, Rina Dao rina.dao!^!<= a href=3D"http://gmail.com">gmail.com <owner-chemistry=ccl.net> wrote:
Dear colleges,

For a fluorescent molecule, the emission= =CE=BB can be calculated=20 by TDDFT. But how can I tell from a calculation that a molecule is not fluo= rescent ? For non-fluorescent molecule, the standard calculation can also yield an emission wavelength, right ? Then how can I identify=20 whether a molecule is fluorescent by calculation ? Is it possible only=20 by experiment ? I am trying to explain a fluorescence quenching=20 experiment which seems to be static quenching (the fluorescent molecule and the quencher forms a ground state complex which is does not glow).=20 How can I give prove to this mechanism ? What property should I=20 calculate ?

thanks in advance~

Rina



--
_____________

Prof. Dr. Andr=C3=A9 Farias de Moura
Department of Chemistry
Federal University of S=C3=A3o Carlos
S=C3=A3o Carlos - Brazil
phone: +55-16-3351-8090
--001a113d516098a139052ff9d82e-- From owner-chemistry@ccl.net Fri Apr 8 11:40:01 2016 From: "Alcides Simao alsimao^^^gmail.com" To: CCL Subject: CCL: How to identify fluorescence by quantum calculation? Message-Id: <-52132-160408113240-12383-rFdwrv37CCmUMecNbYd9AQ-$-server.ccl.net> X-Original-From: Alcides Simao Content-Type: multipart/alternative; boundary=001a11452e4c6dc262052ffae71a Date: Fri, 08 Apr 2016 15:32:25 +0000 MIME-Version: 1.0 Sent to CCL by: Alcides Simao [alsimao^_^gmail.com] --001a11452e4c6dc262052ffae71a Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable By comparing the spin states of both ground and excited state? Best, Alcides A sex, 8/04/2016, 16:30, Andr=C3=A9 Farias de Moura moura(a)ufscar.br < owner-chemistry,,ccl.net> escreveu: > Hi Rina, > > I only do that for teaching purposes, but It seems to me that you cannot > get that information from geometry optimization alone, you'll most likely > get an emission spectra from the excited states optimized geometries. I'd > suggest you to take a look at the papers by Gerrit Groenhof on the QM/MM > molecular dynamics of excited states, which allow the excited states to > find non-radiative paths back to the ground state along QM/MM MD > simulations. > > I hope it helps > > Andre > > On Fri, Apr 8, 2016 at 2:43 AM, Rina Dao rina.dao!^!gmail.com < > owner-chemistry.,,.ccl.net> wrote: > >> Dear colleges, >> >> For a fluorescent molecule, the emission =CE=BB can be calculated by TDD= FT. >> But how can I tell from a calculation that a molecule is not fluorescent= ? >> For non-fluorescent molecule, the standard calculation can also yield an >> emission wavelength, right ? Then how can I identify whether a molecule = is >> fluorescent by calculation ? Is it possible only by experiment ? I am >> trying to explain a fluorescence quenching experiment which seems to be >> static quenching (the fluorescent molecule and the quencher forms a grou= nd >> state complex which is does not glow). How can I give prove to this >> mechanism ? What property should I calculate ? >> >> thanks in advance~ >> >> Rina >> > > > > -- > _____________ > > Prof. Dr. Andr=C3=A9 Farias de Moura > Department of Chemistry > Federal University of S=C3=A3o Carlos > S=C3=A3o Carlos - Brazil > phone: +55-16-3351-8090 > --001a11452e4c6dc262052ffae71a Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

By comparing the spin states of both ground and excited stat= e?

Best,
Alcides


Hi Rina,

I only do that for teaching purposes, but= It seems to me that you cannot get that information from geometry optimiza= tion alone, you'll most likely get an emission spectra from the excited= states optimized geometries. I'd suggest you to take a look at the pa= pers by Gerrit Groenhof on the QM/MM molecular dynamics of excited states, = which allow the excited states to find non-radiative paths back to the grou= nd state along QM/MM MD simulations.

I hope it helps

Andre

On Fri, Apr 8, 2016 at 2:43 AM, Rina Dao= rina.dao!^!gmail.com <owner-chemistry.,,.ccl.net> wrote:
Dear colleges,

For a= fluorescent molecule, the emission =CE=BB can be calculated=20 by TDDFT. But how can I tell from a calculation that a molecule is not fluo= rescent ? For non-fluorescent molecule, the standard calculation can also yield an emission wavelength, right ? Then how can I identify=20 whether a molecule is fluorescent by calculation ? Is it possible only=20 by experiment ? I am trying to explain a fluorescence quenching=20 experiment which seems to be static quenching (the fluorescent molecule and the quencher forms a ground state complex which is does not glow).=20 How can I give prove to this mechanism ? What property should I=20 calculate ?

thanks in advance~

Ri= na



--
_____________

Prof. Dr. Andr=C3=A9 Farias de Moura
Department of Chemistry
Federal University of S=C3=A3o Carlos
S=C3=A3o Carlos - Brazil
phone: +55-16-3351-8090
--001a11452e4c6dc262052ffae71a-- From owner-chemistry@ccl.net Fri Apr 8 14:06:01 2016 From: "Jim Kress jimkress35..gmail.com" To: CCL Subject: CCL: How to identify fluorescence by quantum calculation? Message-Id: <-52133-160408140050-18543-6KdPPZwe+wZ6T8RE6BRkQQ]=[server.ccl.net> X-Original-From: "Jim Kress" Content-Language: en-us Content-Type: multipart/alternative; boundary="----=_NextPart_000_00B3_01D1919F.08FC6000" Date: Fri, 8 Apr 2016 14:00:39 -0400 MIME-Version: 1.0 Sent to CCL by: "Jim Kress" [jimkress35-.-gmail.com] This is a multipart message in MIME format. ------=_NextPart_000_00B3_01D1919F.08FC6000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The ORCA user guide has a great description of how to do this and how to = interpret the results. I=E2=80=99d suggest you look there. https://orcaforum.cec.mpg.de/ =20 Jim =20 > From: owner-chemistry+jimkress35=3D=3Dgmail.com!=!ccl.net = [mailto:owner-chemistry+jimkress35=3D=3Dgmail.com!=!ccl.net] On Behalf Of = Rina Dao rina.dao!^!gmail.com Sent: Friday, April 08, 2016 1:43 AM To: Kress, Jim Subject: CCL: How to identify fluorescence by quantum calculation? =20 Dear colleges, For a fluorescent molecule, the emission =CE=BB can be calculated by = TDDFT. But how can I tell from a calculation that a molecule is not = fluorescent ? For non-fluorescent molecule, the standard calculation can = also yield an emission wavelength, right ? Then how can I identify = whether a molecule is fluorescent by calculation ? Is it possible only = by experiment ? I am trying to explain a fluorescence quenching = experiment which seems to be static quenching (the fluorescent molecule = and the quencher forms a ground state complex which is does not glow). = How can I give prove to this mechanism ? What property should I = calculate ? =20 thanks in advance~ Rina ------=_NextPart_000_00B3_01D1919F.08FC6000 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

The ORCA user guide has a great description of how to do this and how = to interpret the results.=C2=A0 I=E2=80=99d suggest you look = there.

https://orcaforum.cec.mpg.de/<= o:p>

 

Jim

 

From:<= /b> = owner-chemistry+jimkress35=3D=3Dgmail.com!=!ccl.net = [mailto:owner-chemistry+jimkress35=3D=3Dgmail.com!=!ccl.net] On Behalf = Of Rina Dao rina.dao!^!gmail.com
Sent: Friday, April 08, = 2016 1:43 AM
To: Kress, Jim = <jimkress35!=!gmail.com>
Subject: CCL: How to identify = fluorescence by quantum calculation?

 

Dear colleges,


For a fluorescent molecule, the emission =CE=BB = can be calculated by TDDFT. But how can I tell from a calculation that a = molecule is not fluorescent ? For non-fluorescent molecule, the standard = calculation can also yield an emission wavelength, right ? Then how can = I identify whether a molecule is fluorescent by calculation ? Is it = possible only by experiment ? I am trying to explain a fluorescence = quenching experiment which seems to be static quenching (the fluorescent = molecule and the quencher forms a ground state complex which is does not = glow). How can I give prove to this mechanism ? What property should I = calculate ?

 

thanks in = advance~

Rina

------=_NextPart_000_00B3_01D1919F.08FC6000--