Introduction+to+NWChem

=Tutorials for how to use NWChem...=

Contents:
Sample input files, explanation of theory (as best as I can!), benchmarks to optimize our usage at OSC (namely, minimizing queue time so we can get jobs started and minimize our resource usage while making the process of getting incredibly accurate calculations much, much faster), and results for test calculations so you can make sure you're doing things correctly, i.e., MP2 optimization of Xanthaes Cl-Wat dimer and CCSD with MP4 calculated triplets on the H2-H2O dimer from Belpassi.

Why use NWChem over Gaussian?
To use >8 processors in a Gaussian job, it'll cost you even more money for the parallel version, but NWChem is free whether you run it on 1 processor or 1 billion. Clearly, free is better. Additionally, the sorts of calculations we will be looking to perform (all electron, high level of theory, large basis sets) take a considerable amount of time, even on 8 processors! We want to be able to run on 100 processors to knock not just minutes, or hours, but DAYS! off our calculations. Mo' science, mo' papers.

Example series of calculations done on OSC using NWChem6.1 compiled with Intel compilers and MKL:
CHECK OUT THE OSC TIPS PAGE TO LEARN HOW TO PROPERLY CALL NWCHEM ON BOTH THE GLENN AND OAKLEY CLUSTERS

Example SP energy calculation on a chloride-water dimer using g09 optimized coordinates and a user-input basis set. code title "test"

start test

geometry units angstrom Cl     0.000000000   0.000000000  0.000000 O      3.082679918   0.000000000  0.000000 H      2.106637214  -0.139105578  0.000000 H      3.128572335   0.955101182  0.000000 end

basis Cl   S 1467459.0095000             0.11478257194E-04 219756.1643300             0.89234299775E-04 50010.7703010             0.46911086186E-03 14164.8239180             0.19762446133E-02 4620.7465525             0.71419937783E-02 1667.8991635             0.22753219445E-01 650.29199265            0.63959782953E-01 269.38037376            0.15331059238    117.06752106             0.28986952417     52.811766843            0.36348071452 Cl    S    461.42769988             0.18019457578E-01 142.12665355            0.16489442314     54.437838768            0.63891587584 Cl    S     24.160770219            1.0000000 Cl   S      9.7083540306           1.0000000 Cl   S      4.5640696733           1.0000000 Cl   S      2.1194744832           1.0000000 Cl   S      0.75722365394          1.0000000 Cl   S      0.33747224597          1.0000000 Cl   S      0.13860775149          1.0000000 Cl   S      0.54234565513E-01            1.0000000 Cl   P   2501.9457890              0.24242618410E-03 592.88059285            0.21079961749E-02 192.18089186            0.11432693869E-01 72.875710488           0.44956698060E-01 30.436358370           0.13197476145     13.490178902            0.27493639225      6.1478071413           0.38347236372      2.8450944820           0.28871943885 Cl    P    105.39397936            -0.34311760144E-01 6.7369738513          0.64060818902 Cl    P      1.2421095772           1.0000000 Cl   P      0.55669714254          1.0000000 Cl   P      0.23387801464          1.0000000 Cl   P      0.93164490890E-01            1.0000000 Cl   P      0.27256146018E-01            1.0000000 Cl   D      5.1910000000           1.0000000 Cl   D      1.2760000000           1.0000000 Cl   D      0.58300000000          1.0000000 Cl   D      0.24300000000          1.0000000 Cl   D      0.83456538402E-01            1.0000000 Cl   F      0.42300000000          1.0000000 Cl   F      1.0890000000           1.0000000 Cl   G      0.82700000000          1.0000000 O   S 116506.4690800              0.40383857939E-04 17504.3497240             0.31255139004E-03 3993.4513230             0.16341473495E-02 1133.0063186             0.68283224757E-02 369.99569594            0.24124410221E-01 133.62074349            0.72730206154E-01 52.035643649           0.17934429892     21.461939313            0.33059588895 O    S     89.835051252            0.96468652996E-01 26.428010844           0.94117481120 O    S      9.2822824649           1.0000000 O   S      4.0947728533           1.0000000 O   S      1.3255349078           1.0000000 O   S      0.51877230787          1.0000000 O   S      0.19772676454          1.0000000 O   S      0.69638535104E-01            1.0000000 O   P    191.15255810             0.25115697705E-02 45.233356739           0.20039240864E-01 14.353465922           0.93609064762E-01 5.2422371832          0.30618127124      2.0792418599           0.67810501439 O    P      0.84282371424          1.0000000 O   P      0.33617694891          1.0000000 O   P      0.12863997974          1.0000000 O   P      0.43598162776E-01            1.0000000 O   D      3.7750000000           1.0000000 O   D      1.3000000000           1.0000000 O   D      0.44400000000          1.0000000 O   D      0.12546378695          1.0000000 O   F      2.6660000000           1.0000000 O   F      0.85900000000          1.0000000 O   G      1.8460000000           1.0000000 H   S    190.69169000             0.70815167000E-03 28.605532000           0.54678827000E-02 6.5095943000          0.27966605000E-01 1.8412455000          0.10764538000 H    S      0.59853725000          1.0000000 H   S      0.21397624000          1.0000000 H   S      0.80316286000E-01            1.0000000 H   P      2.2920000000           1.0000000 H   P      0.83800000000          1.0000000 H   P      0.29200000000          1.0000000 H   P      0.84063199228E-01            1.0000000 H   D      2.0620000000           1.0000000 H   D      0.66200000000          1.0000000 H   F      1.3970000000           1.0000000 end

charge -1

task mp2 code

Geometry optimization: code start f_wat

charge -1

driver tight maxiter 50 end

geometry symmetry c1 f     -1.251288   -0.044873    0.000000 o     1.204166   -0.049168    0.000000 h     0.153117   -0.079634    0.000000 h     1.373267    0.893015    0.000000 end

basis spherical f   library    aug-cc-pvtz o   library    aug-cc-pvtz h   library    aug-cc-pvtz bqf library f  aug-cc-pvtz bqo library o  aug-cc-pvtz bqh library h  aug-cc-pvtz end

bsse mon ion 1 charge -1 mon wat 2 3 4 end

scf maxiter 100 thresh 1e-8 end

mp2 tight end

task mp2 optimize

code CCSD single point calculation with output density matrix: code start br_wat

charge -1


 * 1) driver
 * 2)  maxiter 50
 * 3)  tight
 * end

geometry symmetry c1 br  0.0000000000       0.0000000000   0.0000000000 o  3.3238257527       0.0000000000   0.0000000000 h  2.3629644882      -0.1931081282   0.0000000000 h  3.3104160296       0.9584110323   0.0000000000 end

basis spherical br  library    aug-cc-pvtz o   library    aug-cc-pvtz h   library    aug-cc-pvtz bqbr library br aug-cc-pvtz bqo library o  aug-cc-pvtz bqh library h  aug-cc-pvtz end

bsse mon ion 1 charge -1 mon wat 2 3 4 end

ccsd maxiter 100 thresh 1e-10 end


 * mp2
 * 1) tight
 * end

tce densmat br.densmat ccsd thresh 1e-10 io ga 2eorb end

task tce energy

dplot TITLE br_dens LimitXYZ units atomic or angstroms  # This line will error out as is, fix to select a unit -12.0  12.0   960   -8.0    8.0   640   -0.025  0.025   3   # I only need a plane, but I need to compute numerical gradients and the Hessian by finite diff spin total gaussian densmat br.densmat output br_dens.cube end

task dplot

code

TPP 06/28/2012