====== Binding Energy of the Benzene Dimer ====== The goal of this exercise is to compute the interaction energy for a π-stacked benzene dimer, with three different methods: * PBE with no dispersion interaction * PBE with parametrized dispersion interaction (PBE-DFTD3) * MP2 (Møller-Plesset perturbation theory) The formula to compute the interaction energy is: \[E_\text{interaction}= E_\text{dimer}- 2 E_\text{benzene}\] The equilibrium distance between the $\pi$-stacked benzene rings has to be obtained through geometry optimization for every level of theory separately. Since the cost of MP2 calculations are very hight, we provide you with the readily optimized geometry for this method. For the other two methods (PBE, PBE-DFTD3) this provided geometry has to be **re-optimized**. You will also require energy calculations of the single benzene molecule. You can extract the coordinates of a single benzene ring with VMD or a text editor. Again, the geometry has to be optimized separately for each method. The correct geometry for MP2-benzene can be found at the end of the exercise and, due to time issues, should not be re-optimized. ===== Questions ===== * Report interaction energy and equilibrium distance for each method ===== Required files ===== ==== DFT-D3 Parameters ==== {{dftd3.dat.gz| Download here}} This file is compressed with gzip. To unpack it run: $ gunzip dftd3.dat.gz ==== Input File ==== &GLOBAL PROJECT benzene_dimer RUN_TYPE ENERGY &END GLOBAL &FORCE_EVAL METHOD Quickstep &DFT !specification of external basis and potential files BASIS_SET_FILE_NAME ./BASIS POTENTIAL_FILE_NAME ./POTENTIALS !section to ensure stable and correct simulations &MGRID CUTOFF 400 &END MGRID &QS METHOD GPW EPS_DEFAULT 1.0E-8 EPS_PGF_ORB 1.0E-8 &END QS &SCF SCF_GUESS ATOMIC EPS_SCF 1.0E-6 MAX_SCF 40 &OT MINIMIZER CG PRECONDITIONER FULL_SINGLE_INVERSE &END &OUTER_SCF EPS_SCF 1.0E-6 MAX_SCF 10 &END &END SCF &POISSON ! Non periodic calculation needs Poisson solver PERIODIC NONE PSOLVER WAVELET &END POISSON !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!This is the section for PBE calculations !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !&XC ! &XC_FUNCTIONAL PBE ! PBE functional ! &END !&END XC !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!This is the section for PBE-DFTD3 calculations !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !&XC ! &XC_FUNCTIONAL PBE ! PBE functional + ... ! &END ! &VDW_POTENTIAL ! ... dispersion interactions ! POTENTIAL_TYPE PAIR_POTENTIAL ! &PAIR_POTENTIAL ! TYPE DFTD3 ! computed with the DFTD3 method ! REFERENCE_FUNCTIONAL PBE ! ! that requires the following parameters (in external file, specified here) ! PARAMETER_FILE_NAME ./dftd3.dat ! R_CUTOFF 15 ! cutoff raddius for the dispersion interactions ! &END PAIR_POTENTIAL ! &END !&END XC !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!This is the section for MP2 calculations !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! &XC ! &XC_FUNCTIONAL NONE ! &END XC_FUNCTIONAL ! &HF ! MP2 runs on top of a parent 100%HF calculation ! FRACTION 1.0 ! 100% hf ! &SCREENING ! Screening of the electronic repulstion up to the given threshold. Section is needed ! EPS_SCHWARZ 1.0E-9 ! &END SCREENING ! &MEMORY ! MAX_MEMORY 1800 ! uses some memory to store data and not recompute each step ! &END ! &END HF ! &WF_CORRELATION ! this section actually sets up MP2 on top of the parent calculation ! METHOD RI_MP2_GPW ! &RI_MP2 ! parameters infulencing the calculation ! BLOCK_SIZE 1 ! Larger BLOCK_SIZE reduces communication but requires more memory ! &END ! &WFC_GPW ! &END ! MEMORY 1800 ! NUMBER_PROC 1 ! &END ! &END XC !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! &END DFT &SUBSYS &CELL ABC [angstrom] 15 15 15 PERIODIC NONE ! Non periodic calculation. &END CELL &COORD ! specification of an external file with coordinates @INCLUDE 'benzene_dimer.coord' &END &TOPOLOGY &CENTER_COORDINATES ! keep atoms away from box borders, would confuse Poisson solver &END &END TOPOLOGY !specification of external basis sets and potentials. The name of the files is given above. &KIND H BASIS_SET cc-TZ RI_AUX_BASIS_SET RI_TZ ! auxiliary basis set, only used by MP2 POTENTIAL GTH-HF-q1 &END KIND &KIND C BASIS_SET cc-TZ RI_AUX_BASIS_SET RI_TZ ! auxiliary basis set, only used by MP2 POTENTIAL GTH-HF-q4 &END KIND &END SUBSYS &END FORCE_EVAL ==== MP2 optimized Coordinates ==== 24 H 8.5709951714 6.1617188657 9.1769626364 C 8.0387778483 5.9757981379 8.2528397815 C 6.6427474511 5.9561428224 8.2430496957 H 6.0937543445 6.1249650636 9.1610309894 C 5.9546039990 5.7314555716 7.0475649921 H 4.8717398728 5.7196290593 7.0404902271 C 6.6635660065 5.5279574532 5.8611612413 H 6.1300650069 5.3536860275 4.9350551393 C 8.0615723757 5.5446390494 5.8709776417 H 8.6121087088 5.3836499080 4.9523278088 C 8.7479484762 5.7683467907 7.0666774749 H 9.8306982448 5.7893185194 7.0736980974 H 6.4284687494 8.8405192314 5.8228620343 H 8.9057373702 8.8752743844 5.8387264727 C 6.9607954533 9.0255100555 6.7471184900 C 8.3568440363 9.0439429763 6.7567676586 C 6.2520232187 9.2329626290 7.9335080936 C 9.0454365692 9.2673522387 7.9522880615 H 5.1692478273 9.2131682112 7.9263504668 H 10.1283042427 9.2780238064 7.9594286415 C 6.9387312641 9.4553058890 9.1292884396 C 8.3367433685 9.4704785560 9.1388664843 H 6.3883177411 9.6163935534 10.0479844468 H 8.8703567259 9.6435467092 10.0651664724 12 H 6.1262627761 7.1212715024 5.4828227563 H 8.5732243361 7.5001625689 5.2622083944 C 6.7242262925 7.2913230904 6.3696466162 C 8.1119736218 7.5056915052 6.2411303862 C 6.1180158107 7.2967148061 7.6292415320 C 8.8755347118 7.7265259429 7.3870351849 H 5.0517765554 7.1342555694 7.7226358929 H 9.9417304949 7.8913874915 7.3106848370 C 6.9022569902 7.5193295225 8.7662224005 C 8.2690952105 7.7333521589 8.6460673286 H 6.4422124064 7.5272841315 9.7460678529 H 8.8675237526 7.9040662104 9.5317665736 ==== Basis Set ==== # H cc-TZ 6 1 0 0 3 1 10.8827241585 -0.0167058885 3.0968750876 -0.0627538300 0.9874518162 -0.1917521975 1 0 0 1 1 0.3450687533 1.0000000000 1 0 0 1 1 0.1492693554 1.0000000000 2 1 1 1 1 1.4070000000 1.0000000000 2 1 1 1 1 0.3880000000 1.0000000000 3 2 2 1 1 1.0570000000 1.0000000000 # C cc-TZ 6 2 0 1 3 1 1 5.3685662937 0.0974901974 -0.0510969367 1.9830691554 0.1041996677 -0.1693035193 0.6978346167 -0.3645093878 -0.3579933930 2 0 1 1 1 1 0.2430968816 1.0000000000 1.0000000000 2 0 1 1 1 1 0.0812865018 1.0000000000 1.0000000000 3 2 2 1 1 1.0970000000 1.0000000000 3 2 2 1 1 0.3180000000 1.0000000000 4 3 3 1 1 0.7610000000 1.0000000000 # # H RI_TZ 10 1 0 0 1 1 8.5115919487 1.0000000000 1 0 0 1 1 1.8744684087 1.0000000000 1 0 0 1 1 0.5632515602 1.0000000000 1 0 0 1 1 0.3698299759 1.0000000000 1 1 1 1 1 2.3711712242 1.0000000000 1 1 1 1 1 1.1794161391 1.0000000000 1 1 1 1 1 0.6050431621 1.0000000000 1 2 2 1 1 1.8092525711 1.0000000000 1 2 2 1 1 1.1433220615 1.0000000000 1 3 3 1 1 1.8065804513 1.0000000000 # C RI_TZ 20 1 0 0 1 1 22.2608165950 1.0000000000 1 0 0 1 1 7.1315246807 1.0000000000 1 0 0 1 1 3.5380450775 1.0000000000 1 0 0 1 1 1.2333453175 1.0000000000 1 0 0 1 1 0.2821517353 1.0000000000 1 0 0 1 1 0.3468258230 1.0000000000 1 1 1 1 1 7.2975063903 1.0000000000 1 1 1 1 1 3.7896065213 1.0000000000 1 1 1 1 1 1.0633834831 1.0000000000 1 1 1 1 1 0.2356430320 1.0000000000 1 1 1 1 1 0.5078423493 1.0000000000 1 2 2 1 1 9.9000557486 1.0000000000 1 2 2 1 1 2.3408375066 1.0000000000 1 2 2 1 1 1.5195338451 1.0000000000 1 2 2 1 1 0.5788522388 1.0000000000 1 2 2 1 1 0.3721345858 1.0000000000 1 3 3 1 1 1.9332589728 1.0000000000 1 3 3 1 1 1.1560553410 1.0000000000 1 3 3 1 1 0.4987261239 1.0000000000 1 4 4 1 1 1.2175667359 1.0000000000 # ==== Pseudo-Potentials ==== # H GTH-HF-q1 1 0 0 0 0.196680577426 2 -4.122010670148 0.685113494453 0 # C GTH-HF-q4 2 2 0 0 0.315416975333 2 -8.867306339232 1.255277018021 1 0.301022709314 1 9.800185699152