PCG Tutorial Basis

download PCG Tutorial Basis

of 51

Transcript of PCG Tutorial Basis

  • 8/3/2019 PCG Tutorial Basis

    1/51

    Using FireFly in education and research @ home

    A short introduction in Computational Chemistry & an overview of strength

    possibilities of PC-Gamess/FireFly and how to make calculations more efficient

    Part II Benchmark Basis/Correlation Correction

    v 1.05

  • 8/3/2019 PCG Tutorial Basis

    2/51

    This benchmark on basis set was done because calculation time strongly

    depends on basis set.

    There are a lot of different sets which describes chemical behaviour, some with

    good approximation to real functions and some with acceptable description.

    Smaller systems can be handled with large basis sets, but if we want to assay a

    molecule with more typical size we have to make some arrangements to handle

    such calculations. To see which smaller basis sets gave comparable

    descriptions to bigger ones in less computational effort there were done some

    benchmarks on typical molecules. We will also see when it is necessary to use

    bigger sets. This may help to get a feeling how calculation time rise with large

    basis sets.

    M. Checinski

  • 8/3/2019 PCG Tutorial Basis

    3/51

    Benchmarks of Basis/Correlation Correction

    In this Chapter are the benchmarks collected, which i made to decide which basis sets

    and Correlation Corrections are useful (quality & time consumption) for typical

    questions in laboratory or which one should be used for educational demands.

    For making a general statement about a good Basisset/Correlation Correction for

    smaller computer(-cluster) it seems to be useful to compare different chemical

    environments. We will study typical organic and inorganic molecules, to find out which

    basis sets are not advisable for some structures.

    Who just want to see the result should jump to the end of this chapter. There is a kindof summary.

  • 8/3/2019 PCG Tutorial Basis

    4/51

    At first we need an imagination of influence of basis sets on computation time.

    Because there are so many factors which have an influence on computational time it is

    impossible to say i.e. one set need two and a half times more computation time than an

    other. But to see how the tendency is i made a comparison of n-alkanes, to see how

    influence of an additional CH2-Group is.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    5/51

    Here we see that different sets have different slopes.

    There are hough differences in computational time of a C8-Alkane computed with a MINI

    and a cc-pVTZ set (here 1:100).

    c2 c3 c4 c5 c6 c7 c8

    0,0

    200,0

    400,0

    600,0

    800,0

    1000,0

    Dependence of basis set on computation time of alkanes

    MINI

    3N21

    6N31

    6N31_dp

    6N311

    6N311_dp

    6N311_2d2p

    TZV_2d2p

    cct

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    6/51

    Here we see that a pd-polarized split-valence set needs more computation time than an

    unpolarized triple-valence set.

    c2 c3 c4 c5 c6 c7 c8

    -50,0

    50,0

    150,0

    250,0

    350,0

    Dependence of basis set on computation time of alkanes

    MINI

    3N21

    6N31

    6N31_dp

    6N311

    6N311_dp

    6N311_2d2p

    TZV_2d2p

    cct

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    7/51

    To compare the basis sets qualitatively we need some properties, which we can

    compare.

    As we have seen the absolute value of total Energy is not the only importantinformation, difference of total Energy by stretching a bond could give a good hint

    about the quality.

    Another property can be the dipole moment, which depends on bond partners and bond

    length. But we can only compare dipole moments with real ones if the molecule were

    measured in gas phase.

    PC-Gamess gives us thermodynamic properties, too. But here we should, compare

    comparable (gas phase) molecules, too.

    We will take a focus on 1D-Potential Energy Surfaces and dipole moment.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    8/51

    At first we will discuss the behaviour of simplest alkane.

    In previous chapters we have discussed the differences of RHF/UHF and HF in general.We have discussed about the cheap correlation correction of Moller-Plesset and the

    popular hybrid calculation of DFT (especial Becke3-LeeYoungParr). Now we will try to

    compare them qualitatively.

    For that we study energy changing by C-H Bond stretching.

    We compare how a HF, HF/MP2 and B3LYP influence the description of this system.

    As basis sets we use the small split valence set 3-21 and the hough triple valence set

    aug-cc-pTVZ with additional diffuse and polarized functions.

    After that we will compare how the popular sets describe bond-stretching of many

    different molecules at UHF/B3LYP level.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    9/51

    Ok, let's start with the 3-21 set.

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    0,00

    0,05

    0,10

    0,15

    0,20

    0,25

    Methan: stretch of C-H Bond

    3N21-RHF

    3N21-UHF3N21-RHF-MP2

    3N21-RHF-B3L

    3N21-UHF-B3Lx

    3N21-UHF-B3L

    distance to equibrillium length

    energydifferencetolowestenergy

    What we can see is that at HF level the description is significant different.

    On the other hand all calculations say that the equilibrium bond distance (at 0.05 A stepping) have relative the

    lowest energy. We will later see that this have not be ususal, but this system is easy to describe.

    And we shall not forget that all basis sets were fitted on such general Molecules to give good functions.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    10/51

    To see better how the different calculations differs we should look at a smaller part of this diagram.

    Here we see that we have three groups ( HF, HF/MP2 and DFT ). For this system the MP2 correction is comparable to

    the computational heavier B3LYP calculation.

    0,550 0,600 0,650

    0,075

    0,085

    0,095

    0,105

    Methan: stretch of C-H Bond

    3N21-RHF3N21-UHF

    3N21-RHF-MP2

    3N21-RHF-B3L

    3N21-UHF-B3Lx

    3N21-UHF-B3L

    distance to equibrillium length

    energydifferenc

    etolowestenergy

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    11/51

    If we use the hough aug-cc-pTZV set we see comparable descriptions of such bond-stretching.

    But now the MP2 correction is not such good like in previous topic.

    0,550 0,600 0,650

    0,075

    0,085

    0,095

    0,105

    Methan: stretch of C-H Bond

    aug-cc-pvtz-RHFaug-cc-pvtz-UHF

    aug-cc-pvtz-RHF-MP2

    aug-cc-pvtz-RHF-B3L

    aug-cc-pvtz-UHF-B3L

    aug-cc-pvtz-UHF-B3Lx

    distance to equibrillium length

    energydifferencetolowestenergy

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    12/51

    Ok, lets put these descriptions together

    Here we see that the ACCT set is much better than 3-21, but this is nothing unexpected =) if

    we know that the ACCT set has for each Orbital 3 possible Orbitals which can be mixed and additional polarization

    and diffuse functions, to make the resulting Orbital more perfect for this chemical environment.

    Don't forget that this is a relative description, absolute values for ACCD are much lower than for 3-21.

    1,000 1,100 1,2000,145

    0,165

    0,185

    Methan: stretch of C-H Bond

    3N21-RHF

    3N21-RHF-MP2

    3N21-UHF-B3L

    aug-cc-pvtz-RHF

    aug-cc-pvtz-RHF-MP2

    aug-cc-pvtz-UHF-B3Lx

    distance to equibrillium length

    energydifferen

    cetolowestenergy

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    13/51

    At this point we should look at the computation effort of these calculations.

    For better comparison we use a here a quite good information which we get from PC-Gamess on each calculation.

    The CPU utilization should be around 100% (or like here on a dual-core 200%), higher values means 100% :)

    But if we have lower values, that means HDD operations which are very very slow. In other words CPU have to wait

    for data to make next Operation. We will later see how dramatically this could be and how PC-Gamess settings can

    help us to avoid such problems. Ok, lets compare the WALL CLOCK times.

    Here we see a big difference between calculation with ACCT and 3-21, on UHF/B3LYPx level where the utilizations

    are most comparable we see a computational difference of 70:1 ! Ok, 12 minutes are not so long, but this is just a

    very small Molecule. For usual molecules it is a hough difference.

    At this point i have to say what B3Lx means. As mentioned PC-Gamess gives us a great flexibility in controlling

    calculations, some less accurate settings seems to make descriptions worser but other have low effects in qualitativedescriptions but big in computational effort. I tested some settings with different molecules to check how to safe

    computational time with small loss of accuracy. In another chapter i will summarize these settings.

    The difference of B3Lx and B3L is just a smaller value of NRAD in $DFT part.

    This is by the way one cause why i made such benchmarks, to check which sets & settings gives best agreement in

    accuracy and time consumption.

    3N21-RHF 3N21-UHF 3N21-RHF-MP2 3N21-RHF-B3L 3N21-UHF-B3Lx 3N21-UHF-B3L

    0,3 0,4 0,5 15,1 10,2 29,0

    228,60% 225,02% 214,35% 200,45% 200,24 200,25%

    349,9 412,3 823,5 496,6 706,1188,05% 186,20% 181,34% 192,95% 197,66%

    Zeit [sec]

    Util 2 CPU

    aug-cc-pvtz-RHF aug-cc-pvtz-UHF aug-cc-pvtz-RHF-MP2 aug-cc-pvtz-RHF-B3L aug-cc-pvtz-UHF-B3Lx aug-cc-pvtz-UHF-B3L

    Zeit [sec]Util 2 CPU

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    14/51

    To see how the absolute differences are here are some impressions of methan.

    There are hough differences between STO2/MINI and a mulit valence set.

    Differences between bigger sets are in another scale.

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    -40,40

    -39,90

    -39,40

    -38,90

    Methan: stretch of C-H Bond

    STO2G

    MINI

    6N31-2pd

    6N311-3p2d

    cc-pVDZ

    aug-cc-pVTZ

    distance to equibrillium length

    energydifferencetolowestenergy

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    15/51

    Here we see that split-valence- and triple-valence-sets are compareable.

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    -40,50

    -40,30

    Methan: stretch of C-H Bond

    6N31-2pd

    6N311-3p2dcc-pVDZ

    aug-cc-pVTZ

    distance to equibrillium length

    energydifferencetolowestenergy

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    16/51

    Here we see difference between HF / HF-MP2 / HF-B3LYP . Basis is 3-21.

    Here there are no differences between RHF & UHF, RHF/B3L & UHF/B3L , and there are low differences between

    RHF/B3L UHF/B3L & UHF/B3Lx

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    -40,30

    -39,80

    Methan: stretch of C-H Bond

    3N21-RHF

    3N21-UHF3N21-RHF-MP2

    3N21-RHF-B3L

    3N21-UHF-B3Lx

    3N21-UHF-B3L

    distance to equibrillium length

    energydifferencetolowestenergy

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    17/51

    -0,10 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 1,10 1,20 1,30

    0,000

    0,050

    0,100

    0,150

    0,200

    0,250

    C-C stretch of Ethan

    distance to equilibrium lenght [A]

    energyrelativetogroundstateE

    Ok, with this experience we see that we should use UHF/B3Lx calculations.

    Now we can start to assay other chemical environments. Let's check how different basis sets describe C-C Bond

    breaking/creating on Ethan, which is a daily topic in Research.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    18/51

    At first we see, that the STO-2G & MINI set is significant different from the other.

    Ethan C-C-Bond is a very simple system, and if these sets have such quality

    problems, we should use them only for didactical usage or fast geometry pre-

    optimization.

    To put focus only the Basis sets, we use a PM3 optimized geometry for this calculation

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    -0,04

    0,06

    0,16

    0,26

    Ethan: variation of C-C Bondlength

    STO-2

    MINIMIDI

    3N21

    DZV

    6N31-2pd

    TZV

    6N311-3p2d

    ACCD

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    19/51

    For small stretch lengths we see that sets with no polarization functions seem not to be very accurate.

    Another informations is that from STO-2 to DZV the relative energy minimum is 0.05 A from equilibrium geometry of

    PM3 optimization.

    To compare the other we should look at some smaller parts of the diagram.

    0,05 0,10 0,15

    -0,002

    0,003

    0,008

    Ethan: variation of C-C Bondlength

    STO-2

    MINI

    MIDI

    3N21

    DZV-pd

    6N31-2pd

    TZV-2pd

    6N311-3p2d

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

    h k f l

  • 8/3/2019 PCG Tutorial Basis

    20/51

    On length around 0.5 A we have another picture. The order of sets is a little bit mixed.

    ACCT, ACCD, 6-311, TZV, DZV builds a close group. 6-31, 3-21 are not far away.

    The MIDI set is a little bit far away and seems to calculate this environment worser than 3-21

    0,45 0,50 0,550,047

    0,052

    0,057

    0,062

    0,067

    Ethan: variation of C-C Bondlength

    STO-2

    MINI

    MIDI3N21

    DZV-pd

    6N31-2pd

    TZV-2pd

    6N311-3p2d

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

    B h k f B i /C l ti C ti

  • 8/3/2019 PCG Tutorial Basis

    21/51

    On a distance of ~ 1 A we can compare this situation with a interaction of 2 Methyl radicals.

    Here we see that the hough sets give lowest energy configuration, for such special environment it's not unusual that

    a set with so many additional Functions and Polarized & Diffuse-functions can describe this situation better.

    Not far away are the split valence sets 6-31 and the 3-21.

    0,95 1,00 1,05

    0,123

    0,128

    0,133

    0,138

    Ethan: variation of C-C Bondlength

    STO-2

    MINI

    MIDI

    3N21DZV-pd

    6N31-2pd

    TZV-2pd

    6N311-3p2d

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

    B h k f B i /C l ti C ti

  • 8/3/2019 PCG Tutorial Basis

    22/51

    Factor time in computational chemistry shall not be underestaminate.

    For this computation we can say that the MINI and STO-2 is qualitatively different.

    The MIDI and 3-21 set is qualitatively comparable to the bigger sets.

    For bigger molecules or a fast preview (or a slow cpu) they are a good agreement.

    Shown time relationship is not exact portable to other calculations, there are so many

    parameters which influence the calculations, but we can say the tendency is accepteable.

    The most CPU utilizations were ~ 100% per CPU, but the higher the molecule and the basis set is the

    larger is the number of stored Integrals. If they are larger than given RAM-Size they have to be

    stored to HDD with the consequence that the CPU utilization breaks significant down and the CPU

    time rise a lot, as seen for the ACCT calculation.

    To give a feeling how important this can be, we can see if we compare the same calculation with

    different RAM access. (MW for $SYSTEM MWORDS=xxx $END)

    For a better recapitulation we shall compare the computational time.

    ~ x times faster

    STO-2 MINI MIDI 3N21 DZV 6N31-2pd TZV 6N311-3p2d ACCD ACCT

    Zeit 13,8 13,5 22,9 22,4 62,9 76,9 140,8 216,0 219,0

    Util 2 CPU 186,41% 200,41% 199,85% 199,75% 195,20% 198,73% 195,31% 193,34% 191,59%

    ACCT MW=180 MW=380

    Zeit 17524,6

    38,77%Util 2 CPU

    Benchmarks of Basis/Correlation Correction

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    23/51

    -0,10 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 1,10 1,20 1,300,000

    0,050

    0,100

    0,150

    0,200

    0,250

    C-H stretch of Acrolein

    distance to equilibrium lenght [A]

    energyrelativetogroundstateE

    As next we prove the basis sets on Acrolein.

    Benchmarks of Basis/Correlation Correction

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    24/51

    At first we see, that the STO-2G & MINI set is significant different from the other,

    again. With such quality problems, we should use them only for didactical usage or

    fast geometry pre-optimization (organic molecules only).

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    -0,04

    0,06

    0,16

    0,26

    Acrolein : Vinyl(CO)-H bond stretch

    STO-2

    MINI

    MIDI3N21

    DZV-pd

    6N31-2pd

    TZV-2pd

    6N311-3p2d

    CCD

    CCT

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    25/51

    On bond length near the equilibrium geometry of a PM3 optimized Acrolein we see

    that many sets haven't their minima.

    0,00 0,05 0,10 0,15-0,002

    0,003

    0,008

    Acrolein : Vinyl(CO)-H bond stretch

    STO-2

    MINI

    MIDI

    3N21

    DZV-pd

    6N31-2pd

    TZV-2pd

    6N311-3p2d

    CCD

    CCT

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    26/51

    Here we see the known groups.

    For better interpretation we should look two pages later on the total energies.

    0,45 0,50 0,55

    0,047

    0,052

    0,057

    0,062

    0,067

    Acrolein : Vinyl(CO)-H bond stretch

    STO-2

    MINI

    MIDI3N21

    DZV-pd

    6N31-2pd

    TZV-2pd

    6N311-3p2d

    CCD

    CCT

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    27/51

    The same situation on long distances. The triple valence sets (TZV, 6-311, CCT) and

    some split valence sets (6-31, DZV, ACCD) runs parallel. STO-2G, MINI, MIDI are far

    away or like 3-21 run qualitatively in another way .

    For a better comparison we should look at the total energy at a distance of 1 A.

    MIDI 3N21 6N31-2pd TZV-2pd 6N311-3p2d CCD CCT ACCD ACCT

    -190,67140 -190,73610 -191,83155 -191,80680 -191,87138 -191,86636 -191,81550 -191,87677 -191,83076 -191,88065

    DZV-pd

    E at 1 A

    0,95 1,00 1,05

    0,108

    0,113

    0,118

    0,123

    Acrolein : Vinyl(CO)-H bond stretch

    STO-2

    MINI

    MIDI

    3N21DZV-pd

    6N31-2pd

    TZV-2pd

    6N311-3p2d

    CCD

    CCT

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    28/51

    STO-2G MINI MIDI 3N21

    Energie -183,80257 -190,60694 -190,77909 -190,84962

    Zeit 23,2 25,4 49,9 45,5

    Ut il 2 CPU 200,04% 200,19% 200,09% 200,05%

    DZV-pd 6N31-2pd TZV-2pd 6N311-3p2d CCD CCT ACCD ACCT

    Energie -191,94875 -191,92146 -191,98662 -191,98066 -191,92643 -191,99154 -191,94354

    Zeit 142,7 173,5 242,7 455,9 137,3 1016,8 447,6

    Ut il 2 CPU 199,39% 198,91% 196,42% 197,38% 199,18% 195,97% 196,03%

    Here we see again how bigger sets rise computational time and which additional effect cpu

    utilization can have on wall clock.

    If we compare the energies of triple and split valence we see a little difference, this is not unusual

    because we have a bigger set on inner and outer orbitals. If we find better inner orbitals with triple

    valence set we will always find lower energy, even if the outer chemical Orbitals are like from a

    split valence.With this assay on acrolein we can make a first conclusion.

    STO-2G, MINI & MIDI is good for fast calculations, we will see later that even this sets describes i.e.

    oxidation of ethan with peroxoaceticacid in a right way.

    But if we will make research more serious we should use at least a 6-31(pd) set.

    Now let's compare computational effort.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    29/51

    -0,10 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 1,10 1,20 1,300,000

    0,050

    0,100

    0,150

    0,200

    0,250

    1-Cl-Propen : HCCl=CHMe bond stretch

    distance to equilibrium lenght [A]

    energyrelativeto

    groundstateE

    Here we test trans-1-Cl-Propen

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    30/51

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    -0,10

    0,00

    0,10

    0,20

    0,30

    0,40

    1-Cl-Propen : HCCl=CHMe bond stretch

    STO-2

    MINI

    MIDI

    3N21

    6N31

    6N31-pd

    DZV-pd

    TZV-2p2d

    6N311-2p2d

    CCD

    CCT

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    31/51

    0,45 0,50 0,55

    0,105

    0,115

    0,125

    0,135

    1-Cl-Propen : HCCl=CHMe bond stretch

    STO-2

    MINI

    MIDI

    3N21

    6N31

    6N31-pd

    DZV-pd

    TZV-2p2d

    6N311-2p2d

    CCD

    CCT

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    32/51

    0,95 1,00 1,05

    0,24

    0,25

    0,26

    0,27

    1-Cl-Propen : HCCl=CHMe bond stretch

    STO-2

    MINI

    MIDI

    3N21

    6N31

    6N31-pd

    DZV-pd

    TZV-2p2d

    6N311-2p2d

    CCD

    CCT

    ACCD

    ACCT

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    33/51

    STO-2G MINI MIDI 3N21

    Energie -555,3482 -574,5341 -574,6387 -574,6706

    Zeit [min] 0,5 0,6 1,2 1,2

    Util 2 CPU 200,16 200,2 200 200,06

    6N31 6N31-pd DZV-pd TZV-2p2d 6N311-2p2d CCD CCT ACCD ACCT

    Energie -577,4500 -577,5057 -577,5326 -577,5850 -577,5795 -577,5401 -577,5949 -577,5507 -577,5974

    Zeit 1,6 3,6 3,8 11,6 10,0 4,3 27,2 18,9 240

    Util 2 CPU 200,01% 199,95% 199,99% 199,98% 199,97% 199,95% 199,97% 199,94% 199,97%

    MIDI 3N21 DZV-pd 6N31-pd TZV-2pd 6N311-3p2d CCD CCT ACCD ACCT

    E at 1 A -574,3811 -574,4115 -577,2856 -577,2496 -577,3339 -577,3258 -577,2884 -577,3425 -577,3028 -577,3464

    Here is the corresponding data.

    The cpu utilization is comparable, so we can better compare computation time now.

    I.e. we get much better description with aug-cc-pVTZ set in comparison to 3-21 but it tooks 200times more computational time.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    34/51

    Now lets take a look at an classical inorganic Molecule

    -0,10 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 1,10 1,20 1,30

    0,000

    0,050

    0,100

    0,150

    0,200

    0,250

    3OCNi-CO stretch of Ni(CO)4

    distance to equilibrium lenght [A]

    energyrelativeto

    groundstateE

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    35/51

    The structure was taken by a TZV-dp UHF/B3Lx optimization.

    Here we see the problem of today basis sets in inorganic chemistry.

    There are so many orbitally changing in the metallic sphere that we need a hough

    choice of functions for every orbital to find a good approximation of the real one.

    -0,30 -0,10 0,10 0,30 0,50 0,70 0,90 1,10 1,30

    0,00

    0,05

    0,10

    Ni(CO)4: Variation of 3(OC)Ni-CO

    MINI

    MIDI

    3N21

    6N31

    6N31-dp

    6N31-2d2p

    TZV

    TZV-dp

    TZV-2d2p

    Mhs-tm

    Mhs-ptm

    Cct

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    36/51

    As we see, there are much bigger differences in qualitative description of an OC Ni interaction, than

    in organic molecules. MINI & MIDI set have even a 0.10 A shorter equilibrium Bondlength and a

    significant different description. In principle it is useful, but in comparison to other there are bad.

    The same apply to 3-21 set.

    When we assay effect of polarization functions we see even at small bond-stretch differences.

    0,05 0,10 0,15

    0,000

    0,010

    0,020

    Ni(CO)4: Variation of 3(OC)Ni-CO

    MINI

    MIDI

    3N21

    6N31

    6N31-dp

    6N31-2d2p

    TZV

    TZV-dpTZV-2d2p

    Mhs-tm

    Mhs-ptm

    Cct

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    37/51

    We also see that a split set of polarization functions has lower effects than one set.

    But if we compare computational effort we see a kind of doubling cpu time.

    6N31 6N31-dp 6N31-2d2p TZV TZV-dp TZV-2d2p

    Zeit [s] 225,7 582,6 1382,7 739,2 1314,1 2462,6

    Ut il 2 CPU 198,48% 197,18% 197,71% 197,85% 197,73% 195,55%

    0,45 0,50 0,55

    0,018

    0,028

    0,038

    Ni(CO)4: Variation of 3(OC)Ni-CO

    MINI

    MIDI

    3N21

    6N316N31-dp

    6N31-2d2p

    TZV

    TZV-dp

    TZV-2d2p

    Mhs-tm

    Mhs-ptm

    Cct

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    38/51

    Here is an overview of total energy of each basis set and calculation time.

    MINI MIDI 3N21 6N31 6N31-dp 6N31-2d2p

    Energie -1951,9668 -1952,7950 -1952,1341 -1961,3597 -1961,5631 -1961,6069

    Zeit 85,9 170,1 176,5 225,7 582,6 1382,7Ut il 2 CPU 199,93% 199,29% 198,41% 198,48% 197,18% 197,71%

    On previous calculations we saw that except STO-2 and MINI most basis sets are acceptable good for

    H,C,O calculations. For research we should use there at least 6-31-(pd). On Ni(CO4) we see that even a

    good split valence set with polarization functions have problems. So one should use for calculations

    which contains transition metals at least a triple valence set.

    We know calculation time hardly depends on chosen basis set, so we should look for some agreements.

    Using of hybrid sets with hough sets for transition metals and smaller sets for first two row elements is

    one strategy. On the other hand we create a kind of artefacts because, different sets have different

    strategies in describing orbitals and we have no consequent description by using hybrids.

    But every one can decide which kind of accuracy he needs.

    For didactical of private usage 6-31 is acceptable, but for research one should use a least a triple

    valence set.

    TZV TZV-dp TZV-2d2p Mhs-tm Mhs-ptm Cct

    Energie -1961,7251 -1961,9104 -1961,9254 -1961,6495 -1955,9510 -1956,1494

    Zeit [s] 739,2 1314,1 2462,6 372,7 6901,0 ~1 day

    Ut il 2 CPU 197,85% 197,73% 195,55% 194,56% 199,05%

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    39/51

    Here is another benchmark of a komplex. Cl-Mn(CO)5 streching Cl-Mn Bond

    -0,10 0,00 0,10 0,20 0,30 0,40 0,50 0,60

    0,00

    0,05

    0,10

    Cl-Mn(CO)5

    distance to equilibrium lenght [A]

    energyrelativeto

    groundstateE

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    40/51

    Text

    -0,15 -0,05 0,05 0,15 0,25 0,35 0,45 0,55 0,65 0,75 0,85

    -0,05

    0,00

    0,06

    Cl-Mn(CO)5

    MINI

    6N31-pd

    CCD

    CCT

    SVP

    TZVP

    ptm2

    ptm3

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    41/51

    Text

    0,05 0,10 0,15

    -0,004

    0,001

    0,006

    Cl-Mn(CO)5

    MINI

    6N31-pd

    CCD

    CCT

    SVP

    TZVP

    ptm2

    ptm3

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    42/51

    Text

    0,45 0,50 0,55

    0,018

    0,023

    0,028

    0,033

    Cl-Mn(CO)5

    MINI

    6N31-pd

    CCD

    CCT

    SVP

    TZVP

    ptm2

    ptm3

    b h k f O h dd l b d h d

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    43/51

    Here is a benchmark of Ni(CO)4 again. With additional basis sets and new hardware.

    -0,10 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 1,10 1,20 1,30

    0,000

    0,050

    0,100

    0,150

    0,200

    0,250

    3OCNi-CO stretch of Ni(CO)4

    distance to equilibrium lenght [A]

    energyrelativeto

    groundstateE

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    44/51

    Text

    -0,15 -0,05 0,05 0,15 0,25 0,35 0,45 0,55 0,65 0,75 0,85

    -0,05

    0,00

    0,06

    Ni(CO)4

    MINI

    6N31-pd

    CCD

    CCT

    SVP

    TZVP

    ptm2

    ptm3

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    45/51

    Text

    0,05 0,10 0,15

    -0,004

    0,001

    0,006

    Ni(CO)4

    MINI

    6N31-pd

    CCD

    CCT

    SVP

    TZVP

    ptm2

    ptm3

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    46/51

    Text

    0,45 0,50 0,55

    0,018

    0,023

    0,028

    0,033

    Ni(CO)4

    MINI

    6N31-pd

    CCD

    CCT

    SVP

    TZVP

    ptm2

    ptm3

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    47/51

    Another important question in chemistry is the difference between some conformations.

    To prove how energy difference depends on basis set we compare cis/trans conformer of but-2-ene.

    Additionally we can compare calculated dipol of each conformer.

    Energy Dipol Time # Iter

    Cis Trans Diff Cis Trans Cis Trans Cis Trans

    STO-2 -150,7977 -150,7994 0,001680 0,164597 0,000196 1,8 1,8 9 9

    MINI -156,2157 -156,2168 0,001119 0,229661 0,000370 2,3 2,2 9 9

    MIDI -156,3047 -156,3067 0,002003 0,179939 0,000298 4,1 3,5 9 8

    3N21 -156,3717 -156,3736 0,001948 0,202529 0,000283 4,0 3,8 9 9

    6N31 -157,1904 -157,1925 0,002071 0,195935 0,000281 5,6 5,0 10 9

    6N31-dp -157,2370 -157,2392 0,002135 0,197658 0,000254 13,5 11,8 10 9

    DZV-dp -157,2521 -157,2539 0,001797 0,228780 0,000283 16,3 14,5 11 10

    6N311-2p2d -157,2812 -157,2833 0,002122 0,212560 0,000245 40,5 38,0 9 9

    TZV-2p2d -157,2892 -157,2912 0,002040 0,249976 0,000247 49,9 43,5 10 9

    ACCT -157,2928 -157,2949 0,002022 0,262794 0,000252 1024,6 1038,8 12 12

    Here we see the same tendency that STO-2 & MINI set is significant different to split or triple zeta sets.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    48/51

    Now let's assay the dipole moment of DMF. Geometry was optimized by 6-311-dp/B3LYP

    Table contain energy, dipole moment, mulliken population diff. and computational time.

    Dipol moment for liquid DMF is 3,86 Debye.

    Benchmarks of Basis/Correlation Correction

  • 8/3/2019 PCG Tutorial Basis

    49/51

    Because in previous test we get some worse mulliken populations with good sets, here is another

    molecule. On 4-aminobenzonitril (6-311(pd) Geometry) we test differences of basis sets.

    Here we see again that there is some kind of inconsistency in describing electron density.

    In some cases we have partial negatively in other partial positively charged nitrogen of nitril-group.

    We would expect a partial negative charge, so here we have a good example that bigger sets don't meen

    automatically better/realer descriptions.

    .. to be continued

  • 8/3/2019 PCG Tutorial Basis

    50/51

    - more benchmarks of metal-organic molecules

    - benchmarks of excited states

    - benchmarks of different hybrid basis sets

  • 8/3/2019 PCG Tutorial Basis

    51/51

    This document is free available.

    It can be used for private or educational requirements.

    It must not be used for commercial aim without agreement of the author.

    It is literary property of Marek Pawel Checinski.

    Leibniz-Institut fr Katalyse e.V.

    http://www.chemie.hu-berlin.de/

    http://www.catalysis.de/

    mail: marek.checinski catalysis.de

    http://www.chemie.hu-berlin.de/http://www.catalysis.de/mailto:marek.checinski%20catalysis.de?subject=[PC-Gamess-Tutorial]%20mailto:marek.checinski%20catalysis.de?subject=[PC-Gamess-Tutorial]%20http://www.catalysis.de/http://www.chemie.hu-berlin.de/