Abstract
Ab initio quantum mechanical methods, including the self-consistent field (SCF), single and double excitation configuration interaction (CISD), the single and double excitation coupled cluster (CCSD), and the single, double, and perturbative triple excitation coupled cluster [CCSD(T)] have been applied to five C5 conformers and four of their C1 counterparts on the potential energy hypersurface of glycine. A large basis set TZ2P+f designated H(5s2p1d/ 3s2p1d) and C,N,O(10s6p2d1f/5s3p2d1f) was chosen to evaluate the importance of d functions on hydrogen and f functions on carbon, nitrogen, and oxygen. A very subtle feature of the glycine potential energy hypersurface is the out-of-plane bending of the C5 structures II (to C\ structure III) and IV (to C1 structure V). Conformer I is the global minimum at all levels of theory. Two of our results are different from previous ab initio predictions: structure II/III is lower in energy than structure IV/V at our highest level of theory, and should be identified as the second minimum. Secondly, although the C1 structure V lies slightly below its C5 counterpart IV at the DZP SCF and TZ2P SCF levels of theory, this ordering is reversed with the TZ2P+f SCF and DZP CISD methods.
| Original language | English |
|---|---|
| Pages (from-to) | 2923-2929 |
| Number of pages | 7 |
| Journal | Journal of the American Chemical Society |
| Volume | 115 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 1993 Apr 1 |
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All Science Journal Classification (ASJC) codes
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
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Glycine Conformational Analysis. / Hu, Ching-Han; Shen, Mingzuo; Schaefer, Henry F.
In: Journal of the American Chemical Society, Vol. 115, No. 7, 01.04.1993, p. 2923-2929.Research output: Contribution to journal › Article
TY - JOUR
T1 - Glycine Conformational Analysis
AU - Hu, Ching-Han
AU - Shen, Mingzuo
AU - Schaefer, Henry F.
PY - 1993/4/1
Y1 - 1993/4/1
N2 - Ab initio quantum mechanical methods, including the self-consistent field (SCF), single and double excitation configuration interaction (CISD), the single and double excitation coupled cluster (CCSD), and the single, double, and perturbative triple excitation coupled cluster [CCSD(T)] have been applied to five C5 conformers and four of their C1 counterparts on the potential energy hypersurface of glycine. A large basis set TZ2P+f designated H(5s2p1d/ 3s2p1d) and C,N,O(10s6p2d1f/5s3p2d1f) was chosen to evaluate the importance of d functions on hydrogen and f functions on carbon, nitrogen, and oxygen. A very subtle feature of the glycine potential energy hypersurface is the out-of-plane bending of the C5 structures II (to C\ structure III) and IV (to C1 structure V). Conformer I is the global minimum at all levels of theory. Two of our results are different from previous ab initio predictions: structure II/III is lower in energy than structure IV/V at our highest level of theory, and should be identified as the second minimum. Secondly, although the C1 structure V lies slightly below its C5 counterpart IV at the DZP SCF and TZ2P SCF levels of theory, this ordering is reversed with the TZ2P+f SCF and DZP CISD methods.
AB - Ab initio quantum mechanical methods, including the self-consistent field (SCF), single and double excitation configuration interaction (CISD), the single and double excitation coupled cluster (CCSD), and the single, double, and perturbative triple excitation coupled cluster [CCSD(T)] have been applied to five C5 conformers and four of their C1 counterparts on the potential energy hypersurface of glycine. A large basis set TZ2P+f designated H(5s2p1d/ 3s2p1d) and C,N,O(10s6p2d1f/5s3p2d1f) was chosen to evaluate the importance of d functions on hydrogen and f functions on carbon, nitrogen, and oxygen. A very subtle feature of the glycine potential energy hypersurface is the out-of-plane bending of the C5 structures II (to C\ structure III) and IV (to C1 structure V). Conformer I is the global minimum at all levels of theory. Two of our results are different from previous ab initio predictions: structure II/III is lower in energy than structure IV/V at our highest level of theory, and should be identified as the second minimum. Secondly, although the C1 structure V lies slightly below its C5 counterpart IV at the DZP SCF and TZ2P SCF levels of theory, this ordering is reversed with the TZ2P+f SCF and DZP CISD methods.
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U2 - 10.1021/ja00060a046
DO - 10.1021/ja00060a046
M3 - Article
AN - SCOPUS:0027196663
VL - 115
SP - 2923
EP - 2929
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 7
ER -