Proton Quantum Confinement
on Symmetric Dimers of Ammonia
and Lower Amine Homologs
Jake A. Tan, Jheng-Wei Li and Jer-Lai Kuo
Abstract Behavior of shared proton in symmetric dimers of ammonia and lower
amine homologs were studied by several theoretical methods. Corresponding
optimized structures by density functional theory show an intuitive hypsochromic
shift as the degree of methylation is enhanced. Inclusion of nuclear quantum effect,
however, changes the whole picture. It was found out that the fundamental vibrational transition corresponding to the shared proton’s stretching motion, ν sp is
counter intuitive. Based from these calculations, there is a bathochromic shift from
ammonia to trimethylamine. These ramifications do clearly indicate that proton is a
quantum object. Furthermore, spectroscopic features for the stretching modes of the
shared proton and H-bond donor-acceptor atoms were proposed.
Keywords Ionic hydrogen bond Á Infrared spectroscopy Á Quantum confinement
1 Introduction
The importance of hydrogen bonded systems can be seen in a plethora of systems.
Acid-base chemistry, protein folding, biocatalysis and molecular recognition are
just to name some. This type of non-covalent interaction is considered to be the
J.A. Tan Á J.-L. Kuo (&)
Institute of Atomic and Molecular Sciences, Academia Sinica,
P.O. Box 23-166, Taipei 10617, Taiwan, ROC
e-mail: jlkuo@pub.iams.sinica.edu.tw
J.A. Tan Á J.-L. Kuo
Molecular Science and Technology Program, Taiwan International Graduate Program,
Academia Sinica, 128 Academia Road, Sec. 2, Nangang, Taipei 115, Taiwan, ROC
J.A. Tan
Department of Chemistry, National Tsing Hua University, 101 Kuang-Fu Road,
Sec. 2, Hsinchu 30013, Taiwan, ROC
J.-W. Li
Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd.,
Taipei 10617, Taiwan, ROC
© Springer International Publishing Switzerland 2015
M.A.C. Nascimento et al. (eds.), Frontiers in Quantum Methods and Applications
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 29,
DOI 10.1007/978-3-319-14397-2_5
77
on Symmetric Dimers of Ammonia
and Lower Amine Homologs
Jake A. Tan, Jheng-Wei Li and Jer-Lai Kuo
Abstract Behavior of shared proton in symmetric dimers of ammonia and lower
amine homologs were studied by several theoretical methods. Corresponding
optimized structures by density functional theory show an intuitive hypsochromic
shift as the degree of methylation is enhanced. Inclusion of nuclear quantum effect,
however, changes the whole picture. It was found out that the fundamental vibrational transition corresponding to the shared proton’s stretching motion, ν sp is
counter intuitive. Based from these calculations, there is a bathochromic shift from
ammonia to trimethylamine. These ramifications do clearly indicate that proton is a
quantum object. Furthermore, spectroscopic features for the stretching modes of the
shared proton and H-bond donor-acceptor atoms were proposed.
Keywords Ionic hydrogen bond Á Infrared spectroscopy Á Quantum confinement
1 Introduction
The importance of hydrogen bonded systems can be seen in a plethora of systems.
Acid-base chemistry, protein folding, biocatalysis and molecular recognition are
just to name some. This type of non-covalent interaction is considered to be the
J.A. Tan Á J.-L. Kuo (&)
Institute of Atomic and Molecular Sciences, Academia Sinica,
P.O. Box 23-166, Taipei 10617, Taiwan, ROC
e-mail: jlkuo@pub.iams.sinica.edu.tw
J.A. Tan Á J.-L. Kuo
Molecular Science and Technology Program, Taiwan International Graduate Program,
Academia Sinica, 128 Academia Road, Sec. 2, Nangang, Taipei 115, Taiwan, ROC
J.A. Tan
Department of Chemistry, National Tsing Hua University, 101 Kuang-Fu Road,
Sec. 2, Hsinchu 30013, Taiwan, ROC
J.-W. Li
Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd.,
Taipei 10617, Taiwan, ROC
© Springer International Publishing Switzerland 2015
M.A.C. Nascimento et al. (eds.), Frontiers in Quantum Methods and Applications
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 29,
DOI 10.1007/978-3-319-14397-2_5
77