| Project/Area Number |
14540464
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Physical chemistry
|
|---|
| Research Institution | University of Tsukuba |
|---|
Principal Investigator |
KIKUCHI Osamu University of Tsukuba, Vice-president, 化学系, 副学長 (30015771)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Ohgi University of Tsukuba, Chemistry, Associate Professor, 化学系, 講師 (80241785)
MORIHASHI Kenji University of Tsukuba, Chemistry, Associate Professor, 化学系, 助教授 (90182261)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
|
|---|
| Keywords | parity-violating energy / spin-orbit coupling / ab initio calculation / L-alanine / D-glyceraldehyde / solvent effect / 溶媒効果 |
|---|
| Research Abstract |
The spin-orbit-coupling SCF (SOC-SCF) wavefunction was obtained on the basis of Breit-Pauli Hamiltonian and generalized spin-orbitals and was used to calculate the parity-violating energy, E <pν> of chiral molecules. The SOC-SCF method gave a reliable variation in the E <pν> value for the conformational change of L-alanine zwitterion (L-ALAZ). The method with the [5s2p/3s] basis set was applied to L-ALAZ in aqueous solution. The solvation was introduced by the continuum model of generalized Born formula, and the E_<pν> map was created as a function of two torsion angles, φ for the NH_3 group and θ for the CO_2 group. In the (φ,θ) map of E_<pν> the positive E_<pν> area is wider than the negative one, and the averaged E_<pν> value was +2.1×10^<20> hartree, indicating that L-ALAZ is more unstable than D-ALAZ in aqueous solution due to the parity-violating weak neutral current interaction.
This conclusion was supported by the Monte Carlo (MC) simulation and ab initio spin-orbit coupling SCF (SOC-SCF) method. The 100 solution structures were picked up at every 1M steps of the MC simulation of the L-ALAZ aqueous solution, and the E_<pν> energy was calculated for the L-ALAZ-(H_2O)_n (n=1-10) clusters in each solution structure. The expectation value of E_<pν> of L-ALAZ was calculated to be positive for thermally stable conformations in aqueous solution at 298K. The MC/MO calculations also provide support for the destabilization of L-ALAZ compared to D-ALAZ at thermally accessible conformations in aqueous solution.
|
