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IV.A.5. Compare Barriers to Internal Rotation for C6H5CHCH2 (Styrene)

Experimental barrier to internal rotation is 13.8 kJ/mol
Experimental data from 1988Cam/Vog:384
V2=1151(20) V4=-276(7) cm-1
Energy Differences (Calculated - Experimental) in kJ/mol
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Methods with predefined basis sets
semi-empirical AM1 -7.7
PM3 -8.3
molecular mechanics DREIDING -8.5

Methods with standard basis sets
3-21G 6-31G* 6-31+G** cc-pVTZ
hartree fock HF -4.5 -1.7 -2.3 -1.5
density functional B3LYP 0.8 4.7 3.1  
3-21G 6-31G* 6-31+G** cc-pVTZ
Moller Plesset perturbation MP2 -7.5 -2.4 -4.0  
3-21G 6-31G* 6-31+G** cc-pVTZ
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.

References

squib reference
1988Cam/Vog:384 W Caminati, B Vogelsanger, A Bauder "Rotational Spectrum of Styrene Observed by Microwave Fourier Transform Spectroscopy" J. Mol. Spec. 128, 384-398 (1988)

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