1995 Fiscal Year Final Research Report Summary
Theoretical study on the proton tunneling in the excited-state hydrogen bond
| Project/Area Number |
06640662
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical chemistry
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
IKUTA Shigeru Tokyo Metropolitan University, General Education Department, Professor, 教養部, 教授 (60112471)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Ab initio MO / Hydrogen bond / Proton transfer / Excited state / Non-empirical molecular orbital method |
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| Research Abstract |
Using the correlation consistent basis set (aug-cc-pVTZ) and the multi-reference configuration interaction (MRCI+D) and restricted coupled-cluster (CCSD (T) ) methods, the potential energy surface as a function of two coordinates, the Cl-Cl distance and the distance of the proton from the center of the two Cl atoms, was investigated in the ground-state HCl_2, excited-state HCl_2 (2^1SIGMA and PI), and the radicals (^2SIGMA and ^2PI). The potential energy curve as a function of the proton movement along the (fixed) Cl-Cl distance was also clarified in the excited HCl_2 anion and the radicals, which are produced by the vertical electronic transitions from the ground-state anions. The natural orbitals obtained in the proceeding full-valence CASSCF method was used in the MRCI+D calculations.
All in the excited-state HCl_2 anions and the radicals in the present study, the double-well potentials were obtained in the anti-symmetric vibrational mode which corresponds to the proton movement along the two Cl atoms. The potential energy barriers range from 7 (^2SIGMA) to 18 (^2PI)kcal/mol. These theoretical studies clearly predict that the proton transfer may occur through the anti-symmetric vibrational mode within the short-period before before the dissociation to the fragments (the excited-state Cl anion and the HCl molecule or the Cl atom and the HCl molecule), if the species produced by the vertical electronic transitions have enough internal energies which can effectively excite the anti-symmetric vibrational mode.
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