Theor Chem Acc (2015) 134:151
1 3
As mentioned above, the aim of this work is to determine
how fragment energies converge to the exact PNOF5 energy
for a given size of the oligomer as function of l . Fragment
energies, E F
l (P n ) , for the oligomers of size ( n = 3, 10) calculated with the 6-31G basis set can be found in Table 1 ,
along with the difference between the two energies per oligomer unit, δ E / n , in kcal/mol. In Fig. 1 , we represent δ E / n
as a function of the largest oligomer size ( l ) used in the
fragment calculation. Calculations were repeated with the
cc-pVDZ basis set for n = (3, 8) and 6-31G(d,p) basis set
Table 1 PNOF5/6-31G energies E ( P n ) and fragment energies E F
l (P n ) (Eq. 10 ), in a.u., for the C n H 2 n +2 oligomers, and the corresponding error,
δ E , in kcal/mol
Geometries were optimized at the B3LYP/6-31+G(d) level of theory
6-31G
cc-pVDZ
6-31G(d,p)
n
E ( P n )
(a.u.)
l
δE/n
(kcal/mol)
n
E ( P n )
(a.u.)
l
δE/n
(kcal/mol)
n
E ( P n )
(a.u.)
l
δE/n
(kcal/mol)
1
−40.24169045
1
−40.25889725
1
−40.262046
2
−79.30382845
2
−79.34030290
2
−79.344005
3
−118.367272
2
−0.273
3
−118.422678
2
−0.203
3
−118.426983
2
−0.213
4
−157.430646
2
−0.399
4
−157.505028
2
−0.300
4
157.509836
2
−0.300
3
0.011
4
3
0.004
3
0.020
5
−196.493955
2
−0.466
5
−196.587301
2
−0.349
5
−196.592634
2
−0.345
3
0.026
3
0.016
3
0.038
4
0.008
4
0.010
4
0.007
6
−235.557275
2
−0.512
6
−235.669573
2
−0.382
6
−235.675439
2
−0.376
3
0.034
3
0.024
3
0.050
4
0.012
4
0.016
4
0.011
5
−0.001
5
0.000
5
0.000
7
−274.620592
2
−0.545
7
−274.751846
2
−0.405
3
0.041
3
0.030
4
0.016
4
0.021
5
−0.002
5
0.000
6
0.000
6
0.000
8
−313.683917
2
−0.570
8
−313.834122
2
−0.422
3
0.045
3
0.034
4
0.018
4
0.024
5
−0.003
5
0.000
6
0.000
6
0.000
7
−0.001
7
0.000
9
−352.747238
2
−0.589
3
0.048
4
0.019
5
−0.003
6
0.000
7
−0.001
8
0.000
10
−391.810562
2
−0.604
3
0.051
4
0.021
5
−0.004
6
0.000
7
−0.001
8
0.000
9
0.000
184
Reprinted from the journal