Subject: TDDFT in Gaussian

From: "Coussens, Betty" <[email-masked]>
Date: Tue, 4 Jun 2002 10:28:04 +0200

Dear all,

I have been using Gaussian98 Revision A.5 for performing a number of TDDFT
calculations on norbornane and norbornane like systems.  As I was performing
this type of computations for the first time I tried reproducing the spectra
presented in a recent paper by Ando et al. (Jpn. J. Appl. Phys. Vol 41
(2002) pp. L105-L108).  Unfortunately, I was not able to do so.  As I had no
idea why, I contacted the authors of this paper.  They were so kind to send
me the output of the TDDFT computation on norbornane they performed
themselves.  Comparing their results with mine, it appeared that although
the excitation energies were similar, the oscillator strengths were totally
different.  The only difference between mine and their calculation is that I
was using symmetry whereas they were not.  I had the plan to use their
optimized norbornane structure and perform exactly the same calculation as
they did.  However, in the meantime, I checked the CCL for messages on
TDDFT.  Based on these messages, it seems that I have to conclude that the
computation of oscillator strenghts was originally not correctly implemented
in Gaussian.  As I am using Revision A.5 whereas Ando et al. have been using
revision A.9 this could probably also explain why I am not able to reproduce
the results of the Ando group.  Can anybody comment on this?

Thanks in advance!

Betty  

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From: Jianquan Chen <[email-masked]>
Date: Tue, 4 Jun 2002 12:22:37 -0400 (EDT)

Hi,
I need to add charge to thousands of molecules. MOPAC is free but slow and
sometimes  changes the moleucular structure. I don't know how MOPAC
works. I have 2 questions.
Can I run MOPAC without optimizing the molecular
structure?
Is there any way to accelate MOPAC? I don't need very accurate charges.

Thanks a lot for any response.

Jianquan Chen

---

From: Jianquan Chen <[email-masked]>
Date: Tue, 4 Jun 2002 12:11:52 -0400 (EDT)

Hi,
I need to convert thousands of 2d sdf file to 3d mol2 files and add
charges. But I met a problem. Concord and Corina is too expensive. Concord
is built in the alchemy2000 that is not very expensive. I have a
question before I buy Alchemy2000. Can I run  Alchemy2000 in batch mode? I
mean, can I use alchemy2000 to convert thousands of 2d file to 3d
automatically.  

Thank you in advance.

jianquan chen

---

From: David Gallagher <[email-masked]>
Date: Tue, 04 Jun 2002 19:17:43 -0700

Hi Jianquan

1.      MOPAC can run just an "SCF" which does not change the geometry. 
This is the fastest way to get partial charges.

2.      The new linear-scaling versions of MOPAC can calculate up to 20,000 
atoms in just a few hours on a Windows desktop computer. With "MOPAC 2002", 
an SCF on a 641 atom protein takes about 3 minutes on a 1000 MHz Pentium 
III. There is more information at 
http://www.cachesoftware.com/mopac/index.shtml

David Gallagher, Fujitsu

At 12:22 PM 6/4/2002 -0400, Jianquan Chen wrote:
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