From owner-chemistry@ccl.net Tue Jan 13 04:56:01 2015 From: "Niveditha Surukonti nivs916*gmail.com" To: CCL Subject: CCL:G: error in internal co-ordinate system in Message-Id: <-50894-150113045417-23752-a5ebg9yxaCUSXIcCCWfCcQ\a/server.ccl.net> X-Original-From: Niveditha Surukonti Content-Type: multipart/alternative; boundary=089e010d8a76d26a2b050c859acb Date: Tue, 13 Jan 2015 15:24:11 +0530 MIME-Version: 1.0 Sent to CCL by: Niveditha Surukonti [nivs916++gmail.com] --089e010d8a76d26a2b050c859acb Content-Type: text/plain; charset=UTF-8 Dear Zork, ModRedundant keyword solved my promblem....!!! Thankyou very much for your suggestion and explanation. with best regards Niveditha Surukonti, Research Scholar, CSIR-IICT, Hyderabad, INDIA. On Fri, Jan 9, 2015 at 8:09 PM, Zork Zou zorkzou(-)gmail.com < owner-chemistry],[ccl.net> wrote: > Dear Niveditha, > > The reason may be that Gaussian is not clever enough to find all the weak > bonds (and the related angles) in a big molecule. OPT(Cartesian) may solve > this problem, but some kinds of OPT calculation were programmed only in > redundant coordinates. > > Please check whether there are some important weak bonds missing in the > table of redundant coordinates. For example, long hydrogen bonds which > exceed internal threshold. If so, add an option OPT(ModRedundant) and > specify those bonds in the format > atom-1 atom-2 B > > Since the problematic molecules are often large (number of atoms from 50 > to 1000+), it's better to write a program to search the missing bonds. > > Best regards, > Wenli > > > On Fri, Jan 9, 2015 at 1:03 AM, niveditha reddy s nivs916_._gmail.com < > owner-chemistry],[ccl.net> wrote: > >> >> Sent to CCL by: "niveditha reddy s" [nivs916]-[gmail.com] >> Dear all, >> i'm performing transition state optimization using qst3 method. >> suprisingly, >> even though i have mentioned cartesian key word, it is giving error in >> internal co-ordinate system. i have also tried giving input in z-matrix >> format, with cartesian keyword which is also resulting in the same error. >> here is my input file. >> >> %mem=2000MB >> %chk=step5reactant.chk >> #p opt(cartesian,qst3,loose,maxcycle=400,calcfc) hf/3-21g >> scf(convergence=5) >> nosym freq=noraman >> >> Title Card >> >> 0 2 >> C 1.35304070 4.83278814 0.86817857 >> geometry specifation follows...... >> >> >> and last few lines of my out put file are... >> >> GradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGrad >> Berny optimization. >> Eigenvalue 121 is 1.19D-06 should be less than 0.000000 >> Eigenvector: >> R3 R2 R49 R1 R46 >> 1 0.63524 0.42437 -0.40049 0.21753 -0.21679 >> A1 A16 R50 R45 A3 >> 1 -0.14879 0.11945 -0.11407 0.11045 0.10781 >> Eigenvalue 122 is 2.86D-07 should be less than 0.000000 >> Eigenvector: >> R2 A2 A1 R3 R49 >> 1 0.42545 -0.42004 0.27879 -0.26774 -0.23335 >> A84 A4 R46 A86 A5 >> 1 0.20585 -0.18463 0.17368 -0.16554 0.13986 >> Eigenvalue 123 is 1.23D-07 should be less than 0.000000 >> Eigenvector: >> D116 D118 R29 R30 D113 >> 1 0.49110 -0.49006 -0.30785 -0.24885 0.14796 >> R32 R20 R68 R19 R46 >> 1 -0.14652 0.13293 0.12573 -0.12553 0.12380 >> NTrRot= -1 NTRed= 562 NAtoms= 42 NSkip= 442 IsLin=F >> Error in internal coordinate system. >> Error termination via Lnk1e in /opt/Apps/g09/l103.exe at Tue Aug 26 >> 15:40:11 >> 2014. >> Job cpu time: 0 days 0 hours 0 minutes 58.2 seconds. >> File lengths (MBytes): RWF= 536 Int= 0 D2E= 0 Chk= 11 >> Scr= >> 1 >> >> >> >> >> i,m unable to understand why it is taking internal cordinates, even >> though i >> have mentioned cartesian co-ordinates. if any one have the explanation for >> this problem, please help me out. >> >> thanks in advance.>> E-mail to subscribers: CHEMISTRY],[ccl.net or use:>> >> E-mail to administrators: CHEMISTRY-REQUEST],[ccl.net or use>> >> >> > --089e010d8a76d26a2b050c859acb Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
=C2=A0Dear Zork,

ModRedundant keyword s= olved my promblem....!!! Thankyou very much for your suggestion and explana= tion.

wit= h best regards
=C2=A0=C2=A0 Niveditha Surukonti,
=C2=A0=C2=A0= =C2=A0 Research Scholar,
=C2=A0=C2=A0=C2=A0 CSIR-IICT,=C2=A0
=
=C2=A0 =C2=A0 Hyderabad, INDIA.

On Fri, Jan 9, 2015 at 8:09 PM, Zork Zou zor= kzou(-)gmail.com <owner-chemistry],[c= cl.net> wrote:
Dear Niveditha,

The reason may be that G= aussian is not clever enough to find all the weak bonds (and the related an= gles) in a big molecule.=C2=A0OPT(Cartesian) may solve this problem, but so= me kinds of OPT calculation were programmed only in redundant coordinates.<= /div>

Please check whether there are some important weak= bonds missing in the table of redundant coordinates. For example, long hyd= rogen bonds which exceed internal threshold.=C2=A0If so, add an option OPT(= ModRedundant) and specify those bonds in the format
=C2=A0 =C2=A0= atom-1 =C2=A0 =C2=A0atom-2 =C2=A0 B

Since the pro= blematic molecules are often large (number of atoms from 50 to 1000+), it&#= 39;s better to write a program to search the missing bonds.

<= /div>
Best regards,
Wenli


On Fri, Jan 9, 2015 at 1:0= 3 AM, niveditha reddy s nivs916_._gmail.com <owner-chemistry],[ccl.net> wrot= e:

Sent to CCL by: "niveditha reddy s" [nivs916]-[gmail.com]
Dear all,
=C2=A0i'm performing transition state optimization using qst3 method. s= uprisingly,
even though i have mentioned cartesian key word, it is giving error in
internal co-ordinate system. i have also tried giving input in z-matrix
format, with cartesian keyword which is also resulting in the same error. here is my input file.

%mem=3D2000MB
%chk=3Dstep5reactant.chk
#p opt(cartesian,qst3,loose,maxcycle=3D400,calcfc) hf/3-21g scf(convergence= =3D5)
nosym freq=3Dnoraman

Title Card

0 2
=C2=A0C=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 1.353= 04070=C2=A0 =C2=A0 4.83278814=C2=A0 =C2=A0 0.86817857
geometry specifation follows......


and last few lines of my out put file are...

=C2=A0GradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradG= rad
=C2=A0Berny optimization.
=C2=A0Eigenvalue=C2=A0 =C2=A0121 is=C2=A0 =C2=A01.19D-06 should be less tha= n=C2=A0 =C2=A0 =C2=A00.000000 Eigenvector:
=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 R3=C2=A0 =C2=A0 =C2=A0 =C2=A0 R2=C2=A0 =C2=A0 =C2=A0 =C2= =A0 R49=C2=A0 =C2=A0 =C2=A0 =C2=A0R1=C2=A0 =C2=A0 =C2=A0 =C2=A0 R46
=C2=A0 =C2=A01=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 0.63524=C2=A0 =C2=A00.42437=C2=A0 -0.40049=C2=A0 =C2=A00.21753= =C2=A0 -0.21679
=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 A1=C2=A0 =C2=A0 =C2=A0 =C2=A0 A16=C2=A0 =C2=A0 =C2=A0 =C2= =A0R50=C2=A0 =C2=A0 =C2=A0 =C2=A0R45=C2=A0 =C2=A0 =C2=A0 =C2=A0A3
=C2=A0 =C2=A01=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0-0.14879=C2=A0 =C2=A00.11945=C2=A0 -0.11407=C2=A0 =C2=A00.11045= =C2=A0 =C2=A00.10781
=C2=A0Eigenvalue=C2=A0 =C2=A0122 is=C2=A0 =C2=A02.86D-07 should be less tha= n=C2=A0 =C2=A0 =C2=A00.000000 Eigenvector:
=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 R2=C2=A0 =C2=A0 =C2=A0 =C2=A0 A2=C2=A0 =C2=A0 =C2=A0 =C2= =A0 A1=C2=A0 =C2=A0 =C2=A0 =C2=A0 R3=C2=A0 =C2=A0 =C2=A0 =C2=A0 R49
=C2=A0 =C2=A01=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 0.42545=C2=A0 -0.42004=C2=A0 =C2=A00.27879=C2=A0 -0.26774=C2=A0 = -0.23335
=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 A84=C2=A0 =C2=A0 =C2=A0 =C2=A0A4=C2=A0 =C2=A0 =C2=A0 =C2= =A0 R46=C2=A0 =C2=A0 =C2=A0 =C2=A0A86=C2=A0 =C2=A0 =C2=A0 =C2=A0A5
=C2=A0 =C2=A01=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 0.20585=C2=A0 -0.18463=C2=A0 =C2=A00.17368=C2=A0 -0.16554=C2=A0 = =C2=A00.13986
=C2=A0Eigenvalue=C2=A0 =C2=A0123 is=C2=A0 =C2=A01.23D-07 should be less tha= n=C2=A0 =C2=A0 =C2=A00.000000 Eigenvector:
=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=A0D116=C2=A0 =C2=A0 =C2=A0 D118=C2=A0 =C2=A0 =C2=A0 =C2=A0R2= 9=C2=A0 =C2=A0 =C2=A0 =C2=A0R30=C2=A0 =C2=A0 =C2=A0 D113
=C2=A0 =C2=A01=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 0.49110=C2=A0 -0.49006=C2=A0 -0.30785=C2=A0 -0.24885=C2=A0 =C2= =A00.14796
=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 R32=C2=A0 =C2=A0 =C2=A0 =C2=A0R20=C2=A0 =C2=A0 =C2=A0 =C2= =A0R68=C2=A0 =C2=A0 =C2=A0 =C2=A0R19=C2=A0 =C2=A0 =C2=A0 =C2=A0R46
=C2=A0 =C2=A01=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0-0.14652=C2=A0 =C2=A00.13293=C2=A0 =C2=A00.12573=C2=A0 -0.12553= =C2=A0 =C2=A00.12380
=C2=A0NTrRot=3D=C2=A0 =C2=A0 -1 NTRed=3D=C2=A0 =C2=A0562 NAtoms=3D=C2=A0 = =C2=A0 42 NSkip=3D=C2=A0 =C2=A0442 IsLin=3DF
=C2=A0Error in internal coordinate system.
=C2=A0Error termination via Lnk1e in /opt/Apps/g09/l103.exe at Tue Aug 26 1= 5:40:11
2014.
=C2=A0Job cpu time:=C2=A0 0 days=C2=A0 0 hours=C2=A0 0 minutes 58.2 seconds= .
=C2=A0File lengths (MBytes):=C2=A0 RWF=3D=C2=A0 =C2=A0 536 Int=3D=C2=A0 =C2= =A0 =C2=A0 0 D2E=3D=C2=A0 =C2=A0 =C2=A0 0 Chk=3D=C2=A0 =C2=A0 =C2=A011 Scr= =3D
1




i,m unable to understand why it is taking internal cordinates, even though = i
have mentioned cartesian co-ordinates. if any one have the explanation for<= br> this problem, please help me out.

=C2=A0 =C2=A0 =C2=A0thanks in advance.



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--089e010d8a76d26a2b050c859acb-- From owner-chemistry@ccl.net Tue Jan 13 07:25:01 2015 From: "Pierre Archirel pierre.archirel-x-u-psud.fr" To: CCL Subject: CCL:G: calculation of molar extinction coefficients Message-Id: <-50895-150113071715-23294-BEMFt2Tywl98zxlaI/Z2OQ*server.ccl.net> X-Original-From: "Pierre Archirel" Date: Tue, 13 Jan 2015 07:17:14 -0500 Sent to CCL by: "Pierre Archirel" [pierre.archirel:_:u-psud.fr] Dear colleagues, I am calculating the molar extinction coefficients of an organic molecule in the following way: 1- molecular simulation with Monte-Carlo sampling of geometries and B3LYP electronic calculation. I calculate 50000 MC steps. 2- selection of one geometry out of 50, after discard of the equilibration zone 3- TDDFT calculations (nstates=20) on the selected list of conformations. 4- convolution of the list of TDDFT rays with the formula (17) of the work: ABP Lever and SI Gorelsky Structure and Bonding Vol. 107 (2004) p. 77-114 For the convolution I take a gaussian with fwhm=0.1 eV. 5- division of the spectrum by the number of conformations in the list. For my molecule I get an excellent wave-length (lambda_max=250 nm) and a molar extinction coefficient too large by a factor 2.5: epsilon = 17000 Lmol^-1cm^-1, measured value epsilon =7000. With BLYP I get a better epsilon (12000) but a poor wave length (280 nm). Obviously a convolution with a larger fwhm (say 0.5 eV) yields the right epsilon value, but a band which is much too large. I see the following plausible issues: 1- the DFT transition dipoles is overestimated 2- the DFT potential surface is too rigid 3- a quantum contribution of the nuclei is lacking Could-you please comment my result and/or give me some biblio on the subject? Many thanks in advance, Pierre Archirel LCP, Universite Paris-Sud, Orsay France pierre.archirel::u-psud.fr From owner-chemistry@ccl.net Tue Jan 13 12:13:01 2015 From: "John McKelvey jmmckel() gmail.com" To: CCL Subject: CCL:G: calculation of molar extinction coefficients Message-Id: <-50896-150113120535-31074-hnIkpUqygxwW/i6XGG5qGg\a/server.ccl.net> X-Original-From: John McKelvey Content-Type: multipart/alternative; boundary=047d7bdc17924fe278050c8ba100 Date: Tue, 13 Jan 2015 12:05:29 -0500 MIME-Version: 1.0 Sent to CCL by: John McKelvey [jmmckel^^^gmail.com] --047d7bdc17924fe278050c8ba100 Content-Type: text/plain; charset=UTF-8 Pierre, One thing that could impact your results is that if dipole based oscillator strengths are used they may be too high. This often found. Do you have access to velocity form oscillator strengths? John On Tue, Jan 13, 2015 at 7:17 AM, Pierre Archirel pierre.archirel-x-u-psud.fr wrote: > > Sent to CCL by: "Pierre Archirel" [pierre.archirel:_:u-psud.fr] > Dear colleagues, > I am calculating the molar extinction coefficients of an organic molecule > in the following way: > 1- molecular simulation with Monte-Carlo sampling of geometries and B3LYP > electronic calculation. I calculate 50000 MC steps. > 2- selection of one geometry out of 50, after discard of the equilibration > zone > 3- TDDFT calculations (nstates=20) on the selected list of conformations. > 4- convolution of the list of TDDFT rays with the formula (17) of the work: > ABP Lever and SI Gorelsky Structure and Bonding Vol. 107 (2004) p. 77-114 > For the convolution I take a gaussian with fwhm=0.1 eV. > 5- division of the spectrum by the number of conformations in the list. > > For my molecule I get an excellent wave-length (lambda_max=250 nm) and a > molar extinction coefficient too large by a factor 2.5: epsilon = 17000 > Lmol^-1cm^-1, > measured value epsilon =7000. > > With BLYP I get a better epsilon (12000) but a poor wave length (280 nm). > Obviously a convolution with a larger fwhm (say 0.5 eV) yields the right > epsilon value, but a band which is much too large. > > I see the following plausible issues: > 1- the DFT transition dipoles is overestimated > 2- the DFT potential surface is too rigid > 3- a quantum contribution of the nuclei is lacking > > Could-you please comment my result and/or give me some biblio on the > subject? > Many thanks in advance, > Pierre Archirel > LCP, Universite Paris-Sud, Orsay France > pierre.archirel::u-psud.fr> > > -- John McKelvey 10819 Middleford Pl Ft Wayne, IN 46818 260-489-2160 jmmckel|-|gmail.com --047d7bdc17924fe278050c8ba100 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Pierre,

One thing that could impact you= r results is that if dipole based oscillator strengths are used they may be= too high.=C2=A0 This often found.=C2=A0 Do you have access to velocity for= m oscillator strengths?

John =C2=A0

On Tue, Jan 13, 2015= at 7:17 AM, Pierre Archirel pierre.archirel-x-u-psud.fr <owner-chemistry|-|ccl.net> wrote:

Sent to CCL by: "Pierre=C2=A0 Archirel" [pierre.archirel:_:u-psud.fr]
Dear colleagues,
I am calculating the molar extinction coefficients of an organic molecule i= n the following way:
1- molecular simulation with Monte-Carlo sampling of geometries and B3LYP e= lectronic calculation. I calculate 50000 MC steps.
2- selection of one geometry out of 50, after discard of the equilibration = zone
3- TDDFT calculations (nstates=3D20) on the selected list of conformations.=
4- convolution of the list of TDDFT rays with the formula (17) of the work:=
ABP Lever and SI Gorelsky Structure and Bonding Vol. 107 (2004) p. 77-114 For the convolution I take a gaussian with fwhm=3D0.1 eV.
5- division of the spectrum by the number of conformations in the list.

For my molecule I get an excellent wave-length (lambda_max=3D250 nm) and a = molar extinction coefficient too large by a factor 2.5: epsilon =3D 17000 L= mol^-1cm^-1,
measured value epsilon =3D7000.

With BLYP I get a better epsilon (12000) but a poor wave length (280 nm). O= bviously a convolution with a larger fwhm (say 0.5 eV) yields the right eps= ilon value, but a band which is much too large.

I see the following plausible issues:
1- the DFT transition dipoles is overestimated
2- the DFT potential surface is too rigid
3- a quantum contribution of the nuclei is lacking

Could-you please comment my result and/or give me some biblio on the subjec= t?
Many thanks in advance,
Pierre Archirel
LCP, Universite Paris-Sud, Orsay France
pierre.archirel::u-psud.fr



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--
John McKelvey
10819 Middleford Pl
Ft Wayne, IN 4= 6818
260-489-2160
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--047d7bdc17924fe278050c8ba100-- From owner-chemistry@ccl.net Tue Jan 13 16:06:01 2015 From: "Werner Crous crous.werner ~ gmail.com" To: CCL Subject: CCL: Transition state optimization of biomolecular system Message-Id: <-50897-150113111741-27357-srS2Vp8m66V5TLMDE2Nu7A^^server.ccl.net> X-Original-From: "Werner Crous" Date: Tue, 13 Jan 2015 11:17:40 -0500 Sent to CCL by: "Werner Crous" [crous.werner#,#gmail.com] Dear all I am trying to do a QM/MM transition state optimization in NWCHEM. I obtained a negative eigenvalue in the Hessian for which I followed the eigenvector. I then did a vibrational analysis that gave me 1 negative frequency. However, projecting out the rotations and translations eliminated this frequency. The frequency was -49.29 cm-1. Visualization showed that the negative frequency corresponds to a rotation around the center of mass of the QM system obviously involving the reaction coordinate as well. I am concerned that there are no low frequencies as one would expect for translations and rotations. What can be the cause of this and is the reason for this result the fact that the wrong mode was followed? Thank you in anticipation. Regards Werner From owner-chemistry@ccl.net Tue Jan 13 16:41:00 2015 From: "Shawkat M Islam sislam###swin.edu.au" To: CCL Subject: CCL: How can I Do Raman & IR in VASP? Message-Id: <-50898-150113153451-26719-pKfxlhX75ZQBaXk5BEm93Q_+_server.ccl.net> X-Original-From: "Shawkat M Islam" Date: Tue, 13 Jan 2015 15:34:50 -0500 Sent to CCL by: "Shawkat M Islam" [sislam[*]swin.edu.au] Hi CCL users, I am new to VASP. I want to perform Raman & IR analysis using VASP? Can anybody please let me know what changes should I have to make in the INCAR file. Any INCAR file with those parameters is highly appreciated. Thanks friend. Shawkat Swinburne University, Australia. sislam*_*swin.edu.au From owner-chemistry@ccl.net Tue Jan 13 22:25:01 2015 From: "singh singh-#-yamanashi.ac.jp" To: CCL Subject: CCL:G: calculation of molar extinction coefficients Message-Id: <-50899-150113222331-825-jA64+WXLB4eY9uordtNmwg-,-server.ccl.net> X-Original-From: singh Content-Language: en-US Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="iso-8859-1" Date: Wed, 14 Jan 2015 03:23:20 +0000 MIME-Version: 1.0 Sent to CCL by: singh [singh ~~ yamanashi.ac.jp] Please use LC-TDDFT. I would recommend LC-BLYP. ________________________________________ > From: owner-chemistry+singh==yamanashi.ac.jp%x%ccl.net on behalf of Pierre Archirel pierre.archirel-x-u-psud.fr Sent: Tuesday, January 13, 2015 9:17 PM To: singh Subject: CCL:G: calculation of molar extinction coefficients Sent to CCL by: "Pierre Archirel" [pierre.archirel:_:u-psud.fr] Dear colleagues, I am calculating the molar extinction coefficients of an organic molecule in the following way: 1- molecular simulation with Monte-Carlo sampling of geometries and B3LYP electronic calculation. I calculate 50000 MC steps. 2- selection of one geometry out of 50, after discard of the equilibration zone 3- TDDFT calculations (nstates=20) on the selected list of conformations. 4- convolution of the list of TDDFT rays with the formula (17) of the work: ABP Lever and SI Gorelsky Structure and Bonding Vol. 107 (2004) p. 77-114 For the convolution I take a gaussian with fwhm=0.1 eV. 5- division of the spectrum by the number of conformations in the list. For my molecule I get an excellent wave-length (lambda_max=250 nm) and a molar extinction coefficient too large by a factor 2.5: epsilon = 17000 Lmol^-1cm^-1, measured value epsilon =7000. With BLYP I get a better epsilon (12000) but a poor wave length (280 nm). Obviously a convolution with a larger fwhm (say 0.5 eV) yields the right epsilon value, but a band which is much too large. I see the following plausible issues: 1- the DFT transition dipoles is overestimated 2- the DFT potential surface is too rigid 3- a quantum contribution of the nuclei is lacking Could-you please comment my result and/or give me some biblio on the subject? Many thanks in advance, Pierre Archirel LCP, Universite Paris-Sud, Orsay France pierre.archirel::u-psud.frhttp://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt