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5.4. HIGH QUALITY WAVE FUNCTIONS AT OPTIMIZED STRUCTURES
161
From the output of the MCLR code
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*
* Harmonic frequencies in cm−1
*
* Intensities in km/mole
*
*
*
* No correction due to curvlinear *
* representations has been done
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Symmetry a
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1
2
Freq.
i2027.40
i2.00
3
i0.07
4
0.05
5
0.07
6
2.02
...
...
Freq.
7
3.57
8
145.36
9
278.41
10
574.44
11
675.27
12
759.94
Freq.
13
927.78
14
943.60
15
1000.07
16
1225.34
17
1265.63
18
1442.57
Freq.
19
1517.91
20
1800.86
21
1878.11
22
2294.83
23
3198.94
24
3262.66
...
...
...
...
we can conclude that we have one imaginary eigenvalue (modes 2-7 corresponds to the
translational and rotational zero frequency modes) and that the structure found with this
procedure indeed is a transition state. A post calculation analysis of the vibrational modes
using the MOLDEN package confirm that the vibrational mode with the imaginary frequency
is a mode which moves the proton from the oxygen to the carbon.
5.4
High quality wave functions at optimized structures
Here we will give an example of how geometrical structures obtained at one level of theory
can be used in an analysis at high quality wave functions. Table 5.9 compiles the obtained
CASSCF geometries for the dimethylcarbene to propene reaction (see Fig 5.8). They can be
compared to the MP2 geometries [37]. The overall agreement is good.
Figure 5.8: Dimethylcarbene to propene reaction path
reactant
transition state
product
The wave function at each of the geometries was proved to be almost a single configuration.
The second configuration in all the cases contributed by less than 5% to the weight of the