Relative Computation Times Relative computation times for camphor (C10H16O), morphine (C17H19NO2) and triacetyldynemicin A (C36H25NO12) for a variety of models are provided below: |
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camphora
|
morphineb
|
triacetyldynemicin Ac
|
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model |
energy
|
geometryd
|
energy
|
geometrye
|
energy
|
geometryf
|
|
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MMFF |
too small |
|
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AM1 |
to measure
|
0.1
|
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HF/3-21G |
1
|
5
|
1g
|
12
|
1h
|
40
|
HF/6-31G* |
7
|
30
|
8
|
110
|
7
|
360
|
HF/6-311+G** |
42
|
180
|
-
|
-
|
-
|
|
EDF1/6-31G* |
12
|
57
|
10
|
140
|
5
|
160
|
EDF1/6-311+G** |
60
|
290
|
50
|
-
|
-
|
-
|
B3LYP/6-31G* |
13
|
65
|
12
|
160
|
10
|
400
|
B3LYP/6-311+G** |
85
|
370
|
76
|
-
|
-
|
-
|
MP2/6-31G* |
27
|
270
|
80
|
2000
|
320
|
-
|
MP2/6-311+G** |
260
|
-
|
650
|
-
|
-
|
-
|
LMP2/6-31G* |
25
|
-
|
50
|
-
|
90
|
-
|
LMP2/6-311+G** |
140
|
-
|
270
|
-
|
-
|
-
|
|
||
a) 131 basis functions for 3-21G, 197 basis functions for
6-31G* and 338 basis functions for 6-311+G** |
The estimates for geometry optimizations assume a fix number of steps (increasing
with molecule size). The required number may vary by as much as a factor of
two depending on the molecule and the "quality" of the guess. Transition
state optimizations will typically require two to three times the number of
optimization steps as equilibrium geometry optimizations. |