ゼオライトRHOにおけるH2拡散に対する量子効果:シビングのための逆運動同位体効果
Lu Gem Gao1,2, Rui Ming Zhang1, Xuefei Xu1
1Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education , Tsinghua University , Beijing 100084 , China.
Journal of the American Chemical Society
|August 1, 2019
まとめ
量子効果により,より重い水素同位体は,より軽いものよりも早くゼオライトRHOで拡散します. この逆運動同位体効果における 量子トンネル効果を上回る 支配的要因はゼロポイントエネルギーです
科学分野:
- 物理化学
- 材料科学
- コンピュータ化学
背景:
- ゼオライトにおけるガス拡散を理解することは,分離と触媒化にとって極めて重要です.
- 量子効果は低温での分子行動に大きな影響を及ぼします
- RHOゼオライトは,ガス貯蔵と分離における潜在的応用がある,よく研究された材料です.
研究 の 目的:
- 純シリカゼオライトRHOにおける水素 (H2) 拡散に対する量子効果を調査する.
- 量子力学的トンネリング,ゼロポイントエネルギー,および熱振動が運動同位体効果 (KIE) に与える影響を明らかにする.
- 量子力学的計算とH2拡散ダイナミクスの古典的処理を比較する.
主な方法:
- カノニカル・バリエーション理論 (CVT) と小曲線トンネリング (SCT) の貢献を組み合わせた.
- 自由度7296度までのゼオライトフレームの振動を含みます.
- 量子化振動分割関数の計算
主要な成果:
- 低温では反動的同位体シート効果が観察され,より重い水素同位体はより軽いものよりも速く拡散した.
- ゼロポイントエネルギー (ZPE) は,量子トンネリングと熱振動効果を上回る逆KIEを引き起こす支配的要因として特定されました.
- ゼオライトの宿主フレームの振動は,低温でのH2拡散ダイナミクスにおいて重要な役割を果たします.
結論:
- 量子効果,特にZPEは,ゼオライトにおけるH2拡散を正確に記述するために重要である.
- この研究は,多孔性物質におけるガス輸送現象を理解するために,量子力学を考慮することの重要性を強調しています.
- ゼオライトのような複雑なシステムの量子ダイナミクスを調査するための堅固な枠組みを提供します.
関連する概念動画
Passive Diffusion: Overview and Kinetics
1.3K
Passive diffusion is a critical process that allows small lipophilic drugs to cross the cell membrane along a concentration gradient. This mechanism's efficiency depends on four primary factors: the membrane's surface area, the drug's lipid-water partition coefficient, the concentration gradient, and the membrane's thickness.
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting...
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting...
1.3K
Quantum Numbers
49.4K
It is said that the energy of an electron in an atom is quantized; that is, it can be equal only to certain specific values and can jump from one energy level to another but not transition smoothly or stay between these levels.
49.4K
Isotopes
63.3K
Elements have a set number of protons that determines their atomic number (Z). For example, all atoms with eight protons are oxygen; however, the number of neutrons can vary for atoms of the same element. The sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have multiple isotopes, for example, carbon-12, carbon-13, and carbon-14.
An element's atomic mass, or weight,...
An element's atomic mass, or weight,...
63.3K
The Quantum-Mechanical Model of an Atom
56.7K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra.
56.7K
Small GTPases - Ras and Rho
5.2K
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
5.2K
Kinetic Molecular Theory: Molecular Velocities, Temperature, and Kinetic Energy
29.7K
The kinetic molecular theory qualitatively explains the behaviors described by the various gas laws. The postulates of this theory may be applied in a more quantitative fashion to derive these individual laws.
29.7K


