CCL: DFT14poll

 Sent to CCL by: "Abrash, Samuel" [sabrash..richmond.edu]
 I think people are taking the words "popularity contest" too
 seriously.  It's just a poll to find out what members of this listserve, who are
 mostly computational chemistry professionals, are using.  I agree that the
 absence of "why" makes this somewhat less useful.  However, I think
 it's useful because if I see a functional that I don't know about used widely,
 I'm going to investigate it.  (Note not blindly use it, but investigate it.)
 Still the why is a useful bit of information.  For  example, I use M062X for
 many of my calculations now, and if asked why, I'd say "because reviewers
 insisted that it's better for complexes than PBEPBE even though my results come
 out the same with either functional, and I wanted my paper published."
 Best,
 Sam
 -----Original Message-----
 > From: owner-chemistry+sabrash==richmond.edu#ccl.net [mailto:owner-chemistry+sabrash==richmond.edu#ccl.net] On Behalf Of Laidig,
 Bill laidig.wd(_)pg.com
 Sent: Sunday, June 01, 2014 8:45 PM
 To: Abrash, Samuel
 Subject: CCL: DFT14poll
 Sent to CCL by: "Laidig, Bill" [laidig.wd=pg.com] I strongly disagree
 with this position.  There are many scientifically valid reasons to know which
 functionals are most popular among theoretical and computational chemists (who,
 I am assuming, are the bulk of this mailing list).  For example:
 1. Even if a functional is clearly inferior to another, if it is used much more
 in real calculations then there may be several reasons to use the inferior
 function:
      a. It is likely more widely implemented meaning you have a wider choice of
 programs
          to use and ways to validate that the calculations were  performed
 correctly.
      b. Wider use means that there is a larger statistical pool of data for
 assessing accuracy,
          etc.  This is often much more important than using a marginally better
 method.  We
          see this in the long-term popularity of methods such as HF/3-21G, and
 B3LYP/6-31G*.
 2. Highly accurate, but arcane theoretical methods make communication of results
 difficult outside the expert community as the reader has little basis for
 assessing the quality of results.  I learned this the hard way in my career in
 industry.
 Most users of computational chemistry want to know what small handful of methods
 can be applied broadly to large classes of problems.  As experts, we are the
 group that is defining the next generation of standard methods so I find it very
 useful to know in what directions we are heading.  Learning why we are using
 functionals can also let the developer of the "next big thing" know
 when their efforts to publicize and promote their methodology has fallen short
 and inspire them to better efforts in the future.
 Bill Laidig
 -----Original Message-----
 > From: owner-chemistry+laidig.wd==pg.com^ccl.net
 > [mailto:owner-chemistry+laidig.wd==pg.com^ccl.net] On Behalf
 Of Robert
 > Molt Jr r.molt.chemical.physics!=!gmail.com
 Sent: Sunday, June 01, 2014 3:07 PM
 To: Laidig, Bill
 Subject: CCL: DFT14poll
 Sent to CCL by: Robert Molt Jr [r.molt.chemical.physics]_[gmail.com]
 Sirs and Madames:
 A "popularity contest" is anathema to science.  The world should not
 weight the opinion of Rodney Bartlett and Robert Molt equally in coupled cluster
 theory.
 Perhaps we should take a poll on what people think the first spherical harmonic
 is?  Or take a poll on whether Planck's constant is too small?
 Evidence and and logic drive science.
 -Robert Molt
 On 06/01/2014 12:26 PM, VÃctor LuaÃa Cabal
 victor,fluor.quimica.uniovi.es wrote:
 > Sent to CCL by: =?iso-8859-1?Q?V=EDctor_Lua=F1a?= Cabal
 > [victor-.-fluor.quimica.uniovi.es]
 > On Sun, Jun 01, 2014 at 06:01:52AM +0000, Rzepa, Henry S
 h.rzepa:imperial.ac.uk wrote:
 >> Can  I suggest that in future this poll be extended to indicate WHY any
 person indicates they  LIKE  a functional? As we all know, the choice of
 functional so often depends on what the property of interest is.
 >>
 >> I suggest initially a relatively short controlled list of properties,
 >> which can then be extended by  âcrowd sourcingâ. Properties
 I have
 >> in mind might be eg
 >>
 >> 1. Reaction barriers
 >> 2. Normal mode analysis
 >> 3. Chiroptical properties
 >> 4. Hydrogen bonds
 >> 5. Excitation energies
 >> 6. Main group elements
 >> 7. Transition metals
 >> 8. Relativistic elements
 >> 9. NMR shieldings, NMR couplings
 >> 10. etc
 >>
 >> That way, we could find out eg the most liked functional for eg
 >> looking at hydrogen bonds.  That would be enormously helpful to
 >> anyone looking to study eg hydrogen bonds.
 > Dear Prof. Rzepa,
 >
 > I have a deep respect for your work, that I use to love, but in this
 > case I dislike strongly the idea of deciding the use of a functional
 > by popularity. There are plenty of examples in which the most popular
 > route was not the best, just the easiest. It took decades, in many
 > cases, to turn back wrong but popular decisions. Two candidates should
 > be advised to create a safe road: the easiest AND the the best
 > founded. Notice that the most popular is not in my list. Popularity
 > can be obtained by well studied techniques that have nothing to do
 > with any real measurement of quality.
 >
 > As for your list of properties it is very useful and I will keep it
 > carefully.
 >
 > Best regards,
 >               Dr. VÃctor LuaÃa
 >
 > --
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