On Friday 30 June 2006 15:32, Giacomo Mulas wrote: > On Fri, 30 Jun 2006, A J Stiles wrote: > > On Friday 30 June 2006 11:01, Jo Shields wrote: > >> Bear in mind, however, that the Gaussian license does not allow > >> comparisons with other software, which can lead to your license being > >> revoked for your entire site. See bannedbygaussian.org > > > > This may very well be unenforcible in some jurisdictions. Even a > > ... (skip) > > > Check your local law very carefully. Your end-user licence agreement > > probably is not worth the paper it is printed on. > > If you read the bannedbygaussian.org site, you will find out that the usual > retaliation is that they will never sell you any subsequent version of the > software if they believe you trespassed their license terms. Since we are > talking about cutting-edge quantum chemistry research,
Sometimes it is also useful to digress as we are doing. I am not sure that a new release of quantum chemical calculation packages represents substantial advancement in the quantum chemical calculation itself. Usually, especially (or only with) commercial software, what the new release promises is something for the real world, such as calculations for your molecule embedded in a solvent, or 13C NMR chem shift evaluation for your molecule (it is your choice to embed it virtually in a solvent or not). For the time being, I consider that smoke, that passes away as smoke passes away. The same is true for molecular mechanics calculations. For the "small molecule with no repetitive units", could you mention a package that is substantially better (I mean in the core mode of the force field, not the speed, which has gained with hardware advancement and the 64bit) than what was available ten years ago? I can not. In particular, when you have systems whose chiroptical properties depend deeply on the solvent used, neither molecular mechanics nor quantum chemical calculations can reproduce it for the time being, no matter how much you pay for the package. What you can hope (in my opinion) is to feed the quantum mechanical package with conformationally minimized structure through moleular mechanics, and hope to understand the basis of the process (electronic transitions, etc) via quantum mechanical calculations. And then guess at with your brain. Do you find anything to this respect that free quantum chemical packages can not offer with respect to commercial packages? The position may be different for molecular mechanics. My impression is of little attention by free software. Most is devoted to proteins/peptides, with force fields that are defied by any complex "small molecule with no repeating units". For molecular mechanics I am at commercial software (do not ask which because I do not advertise) which, however, gives me the source and the right (the invitation actually) to improve on it. This is a difference with respect to the commercial quantum chemical package you mentioned. But this is not to blame you, do not misunderstand me. We strive at solving problems. This is the point. francesco > any current version > is very quickly outdated, which means that this is a very effective > deterrent for anyone who wants to use their code to avoid upsetting them. > > Bye > Giacomo > > -- > _________________________________________________________________ > > Giacomo Mulas <[EMAIL PROTECTED]> > _________________________________________________________________ > > OSSERVATORIO ASTRONOMICO DI CAGLIARI > Str. 54, Loc. Poggio dei Pini * 09012 Capoterra (CA) > > Tel. (OAC): +39 070 71180 248 Fax : +39 070 71180 222 > Tel. (UNICA): +39 070 675 4916 > _________________________________________________________________ > > "When the storms are raging around you, stay right where you are" > (Freddy Mercury) > _________________________________________________________________ > > -- > Il messaggio e' stato analizzato alla ricerca di virus o > contenuti pericolosi da MailScanner, ed e' > risultato non infetto. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
