May 102013
 

I just got a new macbook pro and I am reinstalling a lot of libraries and scientific software that I use in my work.

Mac settings

In the Terminal program I like to use the Pro setting and prefer to use the font Menlo, which I find more readable than the default Monaco.

Programming

I use Xcode and Qt Creator as programming environments. Qt Creator is part of the Qt SDK and is a very fast editor for C++ code.

I cannot start programming without the boost library and a fresh copy of psi4.

Install Homebrew from the Terminal shell by calling:
bash [if you are using the tcsh shell] ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go)"

Then, install autoconf
brew install autoconf

Graphics

Since Mountain Lion does not ship with X11 support I installed XQuartz.

sudo ln -sf /Applications/Utilities/XQuartz.app/ /Applications/Utilities/X11.app

I installed gnuplot using brew

brew install gnuplot

Boost

I downloaded boost 1.53

In  boost/config/stdlib/libcpp.hpp
add:
#if _LIBCPP_VERSION < 1002
#   define BOOST_NO_CXX11_NUMERIC_LIMITS
#endif
Then I ran
./bootstrap.sh –with-libraries=filesystem,python,regex,serialization,system,thread –with-python=/usr/bin/python –with-toolset=clang
./b2 install toolset=clang cxxflags=”-stdlib=libc++” linkflags=”-stdlib=libc++” –prefix=/Users/francesco/Source/boost_1_53_0-bin-c++11
 May 10, 2013  Uncategorized No Responses »
May 302012
 

My new paper with Matthias Hanuer, Andreas Köhn, and Jürgen Gauss has just appeared in JCP.  The significant contribution of this work is to introduce a new wave function for the internally contracted MRCC method based on a sequential transformation of the reference function (sqic-MRCC).  The sqic-MRCC wave function has the form:

\left| \Psi \right> = e^{\hat{T}_1} e^{\hat{T}_2} \cdots \left| \Phi \right> ,

where  \left| \Phi \right> is a multiconfigurational wave function.

Sequencing the exponential operator leads to an advantageous similarity-transformed Hamiltonian, which in turn leads to equations that are less complex with respect to the ic-MRCC method.  What’s most amazing is the fact that the ic-MRCC and sqic-MRCC methods yield almost identical energies.

A sequential transformation approach to the internally contracted multireference coupled cluster method
J. Chem. Phys. 136, 204108 (2012)
http://dx.doi.org/10.1063/1.4718704
 May 30, 2012  Uncategorized No Responses »
May 012012
 

The quantum chemistry program package Psi4 is about to be rolled out in a couple of months.  The new version is not going to be a simple upgrade of Psi3: the program infrastructure was completely rewritten and relies heavily on python, or better Psithon a dialect of python well suited to meet the scripting needs of quantum chemists.  In other words, you can no longer invoke laziness if you don’t  run basis set extrapolation schemes and BSSE corrections: these can be executed with one or few lines of Psithon.  Psi4 is close to 100% C++.  It has a balanced amount of object oriented code and a growing amount of it also relies on STL templates (rarely seen in Psi3).  Plus a subset of boost will ship with Psi4, so you get free smart pointers, tuples, and more goodies.  Unfortunately, Psi4 is not yet iPad friendly.  But who knows, considering the frantic speed  at which the developers have been progressing we can expect any surprise.

A good starting point to follow the latest developments is to visit the psi4 trac page (full access is granted only to developers) and the psi project page.

 

 May 1, 2012  Uncategorized 1 Response »
Apr 182012
 

I have been brushing up on time-dependent DFT and I found this very good review written by  Mark Casida.  It’s part of a collection of articles on TD-DFT published in the Journal of Molecular Structure. Together with Density Functional Theory: An Advanced Course by Engel and Dreizler these are excellent resources to learn more about DFT.  The book covers several advanced topics and therefore at times it’s a bit technical.

P.S. I just noticed a new perspective article on DFT by Burke published in the Journal of Chemical Physics.

 April 18, 2012  Uncategorized No Responses »
Nov 072011
 

I apologize if some of the features of the web site are not working properly. I no longer own the domain abinitio.cc but some of my links still point to it. I will try to fix this problem soon (hopefully).

 November 7, 2011  Uncategorized No Responses »
Nov 042011
 

Computational methods for extended and periodic systems (solids, surfaces) are dominated by density functional theory, but in the past fifteen years alternative approaches have been suggested. Among these there is dynamical mean field theory. The Chan group recently has been pioneering the use of DMFT theory in conjunction with highly-accurate wave function methods like configuration interaction theory. Check out this talk by Chan: Dynamical Mean Field Theory from a Quantum Chemistry Perspective, it’s a good introduction.
For more details consult the JCP paper of Dominika Zgid and Garnet Chan: Dynamical mean-field theory from a quantum chemical perspective.

 November 4, 2011  Uncategorized No Responses »