The pyqchem from europj

pyqchem's Introduction

Python Quantum Chemistry (pyqchem)

Joshua J Goings, [email protected], (2013)

Python Quantum Chemistry (pyqchem) is a series of routines that I use to test new ideas in Electronic Structure theory. There are a series of folders of atoms and small molecules that contain important integral files to be used in all SCf and post-SCF calculations. To run, just execute pyqchem.py followed by the folder of interest.  

For example:
	>>$ python pyqchem.py h2_3-21G 

Would execute the pyqchem.py script on the folder h2_3-21G, which contains all the precomputed atomic-orbital basis integrals. The type of calculation is changed by editing the pyqchem.py script itself. Say I wanted to perform an MP2 calculation on H2 in a 3-21G basis. I open pyqchem.py, and edit at the top:

pyqchem.py
-----------
.
.
.

""" Edit below to perform the calculation desired
"""

do_DIIS      = True     <=== DIIS acceleration (just keep on)
do_ao2mo     = True     <=== Set to true so we use our optimized (MO) orbitals from SCF
do_mp2       = True     <=== Set to True so we do an MP2 
do_cistdhf   = False    <=== Set to False so we don't do a CIS/TDHF
do_ccsd      = False    <=== Set to False so we don't do CCSD 
do_eomccsd   = False    <=== Set to False so we don't do EOM-CCSD     
do_eommbpt2  = False    <=== Set to False so we don't do EOM-MBPT2
do_eommbptp2 = False    <=== Set to False so we don't do EOM-MBPT(2)
do_eommbptd  = False    <=== Set to False so we don't do EOM-MBPT(D)
printops     = True     <=== True prints more stuff
convergence  = 1.0e-8   <=== Our iterative convergence criteria 

.
.
.
-----------

Then run:
    >>$ python pyqchem.py h2_3-21G

And you'll see the pretty output dump to your terminal :)

Note that the routines aren't really optimized (hey, it's my practice code!), and if you try some heavy stuff like EOM-CCSD on even methane you will be waiting a while. It'll run just fine for MP2 and CIS/TDHF though.

That's all there is to it! Feel free to edit to your liking, but if you take any ideas from it I ask you give me credit.

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