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IV.A.5. Compare Barriers to Internal Rotation for H2NCH2COOH (Glycine)

Experimental barrier to internal rotation is 14.0 kJ/mol
Experimental data from 1991Iij/Tan:257
V1=454.7, V2=944.4 cm-1
Energy Differences (Calculated - Experimental) in kJ/mol
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Methods with predefined basis sets
semi-empirical AM1 -7.5
PM3 -8.3
molecular mechanics DREIDING -8.1
UFF -3.4

Methods with standard basis sets
3-21G 6-31G* 6-31+G**
hartree fock HF 4.2 -0.6 -1.9
density functional B3LYP 0.1 -3.1 -4.5
3-21G 6-31G* 6-31+G**
Moller Plesset perturbation MP2 1.3 -2.9 -4.9
3-21G 6-31G* 6-31+G**
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
1991Iij/Tan:257 K Iijima, K Tanaka, S Onuma "Main conformer of gaseous glycine: molecular structure and rotational barrier from electron diffraction data and rotational constants" J. Mol. Struct. 246 (1991), 257-266

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