Ab initio and reaction dynamic calculations for three-atom reactions using potential energy surface and reaction coordinate calculations using relativistic effective core potentials. = 에너지 표면을 이용한 삼원자 분자 반응에 대한 양자화학 및 반응동력학 계산과 유효중심장 이론을 이용한 반응 경로 계산

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Potential energy surfaces are generated for the reactions of Ca + $H_2$ → CaH + H, Ti + NO → TiO + N, Ti + $O_2$ → TiO + O, Sc+NO → ScO+N, Sc + O$_2$ → ScO + O, LiH + H → Li + $H_2$ using ab initio method. Six $^1$A` potential energy surfaces of the Ca + $H_2$ system have been calculated using an effective-core potential and a core-polarization potential for Ca atom. The 2 $^1A`$ surface, made from Ca(4s3d, $^1D$), has a very stable intermediate, and crosses with the ground state (1 $^1A`$) potential energy surface in $C_{2v}$ geometry. A diabatic coupling between these two surfaces can result in the CaH product. For the reaction between transition metals and oxidant molecules, charge transfer from metal to oxidant molecule occurred and energy barrier is present, coming from the ionic-neutral potential energy surface crossing. The end-on attack appeared to be the most efficient for the reaction of Ti + NO → TiO + N and Sc+NO → ScO+N, while the side-on attack is the most efficient for the reaction of $Ti + O_2 → TiO + O$ and $Sc + O_2 → ScO + O$. Trajectory calculations on the interpolated potential energy surface which was made by IMLS/Shepard interpolation scheme illustrate that the initial vibrational content of LiH plays a rather minor role in the sense that the reactive cross section depends little on it, and the reactive cross section has maximum value, when the initial collision energy is about 0.1 eV. The endothermic reaction of $Li + H_2 → LiH + H$ requires highly excited $H_2$ molecules for it to occur at low collision energy (ν≥ 4), and it is more efficient to put the same amount energy into the $H_2$ vibration energy rather than translational energy. IRC and DRC calculations were performed and their results are analyzed by vibration modes of reactants and products. Our works show that reaction mechanisms and some essential features can be predicted by analyzing the potential surfaces or reaction dynamic calculations.
Advisors
Lee, Yoon-Supresearcher이윤섭researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
2002
Identifier
174665/325007 / 000985035
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2002.2, [ x, 81 p. ]

Keywords

three atom; potential energy surface; Ab initio; reaction coordinate; 반응 경로; 유효중심장; 양자화학; 에너지 표면; 삼원자 분자

URI
http://hdl.handle.net/10203/31574
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=174665&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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