PCGK66PCOVER Powerful software for creative minds. PCG ...
PCG Tutorial Basis

Upload
francisbokingo 
Category
Documents

view
242 
download
1
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 PCGamess/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 nalkanes, to see how
influence of an additional CH2Group 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 C8Alkane computed with a MINI
and a ccpVTZ 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 pdpolarized splitvalence set needs more computation time than an
unpolarized triplevalence 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.
PCGamess gives us thermodynamic properties, too. But here we should, compare
comparable (gas phase) molecules, too.
We will take a focus on 1DPotential 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 MollerPlesset and the
popular hybrid calculation of DFT (especial Becke3LeeYoungParr). Now we will try to
compare them qualitatively.
For that we study energy changing by CH 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 321 and the hough triple valence set
augccpTVZ with additional diffuse and polarized functions.
After that we will compare how the popular sets describe bondstretching 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 321 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 CH Bond
3N21RHF
3N21UHF3N21RHFMP2
3N21RHFB3L
3N21UHFB3Lx
3N21UHFB3L
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 CH Bond
3N21RHF3N21UHF
3N21RHFMP2
3N21RHFB3L
3N21UHFB3Lx
3N21UHFB3L
distance to equibrillium length
energydifferenc
etolowestenergy
Benchmarks of Basis/Correlation Correction

8/3/2019 PCG Tutorial Basis
11/51
If we use the hough augccpTZV set we see comparable descriptions of such bondstretching.
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 CH Bond
augccpvtzRHFaugccpvtzUHF
augccpvtzRHFMP2
augccpvtzRHFB3L
augccpvtzUHFB3L
augccpvtzUHFB3Lx
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 321, 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 321.
1,000 1,100 1,2000,145
0,165
0,185
Methan: stretch of CH Bond
3N21RHF
3N21RHFMP2
3N21UHFB3L
augccpvtzRHF
augccpvtzRHFMP2
augccpvtzUHFB3Lx
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 PCGamess on each calculation.
The CPU utilization should be around 100% (or like here on a dualcore 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 PCGamess 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 321, 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 PCGamess 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.
3N21RHF 3N21UHF 3N21RHFMP2 3N21RHFB3L 3N21UHFB3Lx 3N21UHFB3L
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
augccpvtzRHF augccpvtzUHF augccpvtzRHFMP2 augccpvtzRHFB3L augccpvtzUHFB3Lx augccpvtzUHFB3L
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 CH Bond
STO2G
MINI
6N312pd
6N3113p2d
ccpVDZ
augccpVTZ
distance to equibrillium length
energydifferencetolowestenergy
Benchmarks of Basis/Correlation Correction

8/3/2019 PCG Tutorial Basis
15/51
Here we see that splitvalence and triplevalencesets 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 CH Bond
6N312pd
6N3113p2dccpVDZ
augccpVTZ
distance to equibrillium length
energydifferencetolowestenergy
Benchmarks of Basis/Correlation Correction

8/3/2019 PCG Tutorial Basis
16/51
Here we see difference between HF / HFMP2 / HFB3LYP . Basis is 321.
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 CH Bond
3N21RHF
3N21UHF3N21RHFMP2
3N21RHFB3L
3N21UHFB3Lx
3N21UHFB3L
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
CC 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 CC 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 STO2G & MINI set is significant different from the other.
Ethan CCBond 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 CC Bondlength
STO2
MINIMIDI
3N21
DZV
6N312pd
TZV
6N3113p2d
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 STO2 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 CC Bondlength
STO2
MINI
MIDI
3N21
DZVpd
6N312pd
TZV2pd
6N3113p2d
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, 6311, TZV, DZV builds a close group. 631, 321 are not far away.
The MIDI set is a little bit far away and seems to calculate this environment worser than 321
0,45 0,50 0,550,047
0,052
0,057
0,062
0,067
Ethan: variation of CC Bondlength
STO2
MINI
MIDI3N21
DZVpd
6N312pd
TZV2pd
6N3113p2d
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 & Diffusefunctions can describe this situation better.
Not far away are the split valence sets 631 and the 321.
0,95 1,00 1,05
0,123
0,128
0,133
0,138
Ethan: variation of CC Bondlength
STO2
MINI
MIDI
3N21DZVpd
6N312pd
TZV2pd
6N3113p2d
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 STO2 is qualitatively different.
The MIDI and 321 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 RAMSize 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
STO2 MINI MIDI 3N21 DZV 6N312pd TZV 6N3113p2d 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
CH 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 STO2G & MINI set is significant different from the other,
again. With such quality problems, we should use them only for didactical usage or
fast geometry preoptimization (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
STO2
MINI
MIDI3N21
DZVpd
6N312pd
TZV2pd
6N3113p2d
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 0,150,002
0,003
0,008
Acrolein : Vinyl(CO)H bond stretch
STO2
MINI
MIDI
3N21
DZVpd
6N312pd
TZV2pd
6N3113p2d
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
STO2
MINI
MIDI3N21
DZVpd
6N312pd
TZV2pd
6N3113p2d
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, 6311, CCT) and
some split valence sets (631, DZV, ACCD) runs parallel. STO2G, MINI, MIDI are far
away or like 321 run qualitatively in another way .
For a better comparison we should look at the total energy at a distance of 1 A.
MIDI 3N21 6N312pd TZV2pd 6N3113p2d CCD CCT ACCD ACCT
190,67140 190,73610 191,83155 191,80680 191,87138 191,86636 191,81550 191,87677 191,83076 191,88065
DZVpd
E at 1 A
0,95 1,00 1,05
0,108
0,113
0,118
0,123
Acrolein : Vinyl(CO)H bond stretch
STO2
MINI
MIDI
3N21DZVpd
6N312pd
TZV2pd
6N3113p2d
CCD
CCT
ACCD
ACCT
Benchmarks of Basis/Correlation Correction
Benchmarks of Basis/Correlation Correction

8/3/2019 PCG Tutorial Basis
28/51
STO2G 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%
DZVpd 6N312pd TZV2pd 6N3113p2d 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.
STO2G, 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 631(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
1ClPropen : HCCl=CHMe bond stretch
distance to equilibrium lenght [A]
energyrelativeto
groundstateE
Here we test trans1ClPropen
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
1ClPropen : HCCl=CHMe bond stretch
STO2
MINI
MIDI
3N21
6N31
6N31pd
DZVpd
TZV2p2d
6N3112p2d
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
1ClPropen : HCCl=CHMe bond stretch
STO2
MINI
MIDI
3N21
6N31
6N31pd
DZVpd
TZV2p2d
6N3112p2d
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
1ClPropen : HCCl=CHMe bond stretch
STO2
MINI
MIDI
3N21
6N31
6N31pd
DZVpd
TZV2p2d
6N3112p2d
CCD
CCT
ACCD
ACCT
Benchmarks of Basis/Correlation Correction

8/3/2019 PCG Tutorial Basis
33/51
STO2G 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 6N31pd DZVpd TZV2p2d 6N3112p2d 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 DZVpd 6N31pd TZV2pd 6N3113p2d 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 augccpVTZ set in comparison to 321 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
3OCNiCO 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 TZVdp 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)NiCO
MINI
MIDI
3N21
6N31
6N31dp
6N312d2p
TZV
TZVdp
TZV2d2p
Mhstm
Mhsptm
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 321 set.
When we assay effect of polarization functions we see even at small bondstretch differences.
0,05 0,10 0,15
0,000
0,010
0,020
Ni(CO)4: Variation of 3(OC)NiCO
MINI
MIDI
3N21
6N31
6N31dp
6N312d2p
TZV
TZVdpTZV2d2p
Mhstm
Mhsptm
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 6N31dp 6N312d2p TZV TZVdp TZV2d2p
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)NiCO
MINI
MIDI
3N21
6N316N31dp
6N312d2p
TZV
TZVdp
TZV2d2p
Mhstm
Mhsptm
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 6N31dp 6N312d2p
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 STO2 and MINI most basis sets are acceptable good for
H,C,O calculations. For research we should use there at least 631(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 631 is acceptable, but for research one should use a least a triple
valence set.
TZV TZVdp TZV2d2p Mhstm Mhsptm 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. ClMn(CO)5 streching ClMn Bond
0,10 0,00 0,10 0,20 0,30 0,40 0,50 0,60
0,00
0,05
0,10
ClMn(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
ClMn(CO)5
MINI
6N31pd
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
ClMn(CO)5
MINI
6N31pd
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
ClMn(CO)5
MINI
6N31pd
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
3OCNiCO 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
6N31pd
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
6N31pd
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
6N31pd
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 but2ene.
Additionally we can compare calculated dipol of each conformer.
Energy Dipol Time # Iter
Cis Trans Diff Cis Trans Cis Trans Cis Trans
STO2 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
6N31dp 157,2370 157,2392 0,002135 0,197658 0,000254 13,5 11,8 10 9
DZVdp 157,2521 157,2539 0,001797 0,228780 0,000283 16,3 14,5 11 10
6N3112p2d 157,2812 157,2833 0,002122 0,212560 0,000245 40,5 38,0 9 9
TZV2p2d 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 STO2 & 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 6311dp/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 4aminobenzonitril (6311(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 nitrilgroup.
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 metalorganic 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.
LeibnizInstitut fr Katalyse e.V.
http://www.chemie.huberlin.de/
http://www.catalysis.de/
mail: marek.checinski catalysis.de
http://www.chemie.huberlin.de/http://www.catalysis.de/mailto:marek.checinski%20catalysis.de?subject=[PCGamessTutorial]%20mailto:marek.checinski%20catalysis.de?subject=[PCGamessTutorial]%20http://www.catalysis.de/http://www.chemie.huberlin.de/