TY - JOUR
T1 - Isotope effect in dihydrogen-bonded systems
T2 - Application of the analytical energy gradient method in the nuclear orbital plus molecular orbital theory
AU - Nakai, Hiromi
AU - Ikabata, Yasuhiro
AU - Tsukamoto, Yasuhiro
AU - Imamura, Yutaka
AU - Miyamoto, Kaito
AU - Hoshino, Minoru
PY - 2007/10/21
Y1 - 2007/10/21
N2 - We investigate isotope effects in dihydrogen systems using the nuclear orbital plus molecular orbital (NOMO) theory, which simultaneously determines nuclear and electronic wave functions without the Born-Oppenheimer approximation. In order to estimate the vibrational averaging bond distances, the analytical energy gradients are used for the NOMO theory. The bond distances of three dihydrogen-bonded systems, namely H3NX+ XBeH, LiX XC2H and H2BX XF for X = H, D and T, are obtained. The X X bond distances decrease with respect to the substitution T D H, which is contrary to the behaviour of typical hydrogen bonds. This indicates that isotope effects strengthen the X X bond. This behaviour is analogous to the Ubbelohde effect observed in the solid phase.
AB - We investigate isotope effects in dihydrogen systems using the nuclear orbital plus molecular orbital (NOMO) theory, which simultaneously determines nuclear and electronic wave functions without the Born-Oppenheimer approximation. In order to estimate the vibrational averaging bond distances, the analytical energy gradients are used for the NOMO theory. The bond distances of three dihydrogen-bonded systems, namely H3NX+ XBeH, LiX XC2H and H2BX XF for X = H, D and T, are obtained. The X X bond distances decrease with respect to the substitution T D H, which is contrary to the behaviour of typical hydrogen bonds. This indicates that isotope effects strengthen the X X bond. This behaviour is analogous to the Ubbelohde effect observed in the solid phase.
KW - Analytical energy gradient
KW - Dihydrogen-bonded system
KW - Isotope effect
KW - Nuclear orbital plus molecular orbital theory
KW - Vibrational averaging shift
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U2 - 10.1080/00268970701618416
DO - 10.1080/00268970701618416
M3 - Article
AN - SCOPUS:38849166113
VL - 105
SP - 2649
EP - 2657
JO - Molecular Physics
JF - Molecular Physics
SN - 0026-8976
IS - 19-22
ER -