# Assessment of density functionals for pi systems: Energy differences between cumulenes and poly-ynes; proton affinities, bond length alternation, and torsional potentials of conjugated polyenes; and proton affinities of conjugated Shiff bases.

@article{Zhao2006AssessmentOD, title={Assessment of density functionals for pi systems: Energy differences between cumulenes and poly-ynes; proton affinities, bond length alternation, and torsional potentials of conjugated polyenes; and proton affinities of conjugated Shiff bases.}, author={Yan Zhao and D. Truhlar}, journal={The journal of physical chemistry. A}, year={2006}, volume={110 35}, pages={ 10478-86 } }

Woodcock et al. [J. Phys. Chem. A 2002, 106, 11923] pointed out that no density functional was able to obtain the correct sign of the relative energies of the allene and propyne isomers of C3H4 and that density functional theory (DFT) predicts that poly-ynes are insufficiently stabilized over cumulenes for higher homologues. In the present work, we show that the recent M05 density functional predicts the correct ordering of allene and propyne and gives a mean unsigned error (MUE) of only 1.8… Expand

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#### References

SHOWING 1-3 OF 3 REFERENCES

How and why coupled-cluster theory became the pre-eminent method in an ab into quantum chemistry

- Chemistry
- 2005

Publisher Summary The correlation problem has been a focal point of quantum chemistry for more than 40 years. Coupled-cluster methods typically offer its best numerical solution for molecules and… Expand

AB INITIO Molecular Orbital Theory

- Physics
- 1986

Describes and discusses the use of theoretical models as an alternative to experiment in making accurate predictions of chemical phenomena. Addresses the formulation of theoretical molecular orbital… Expand