对于H+++H2低温碰撞的Ortho-Para转换:一个完全紧密结合的依赖时间的波束研究
Saikat Hazra1, Koushik Naskar1, Satrajit Adhikari1
1School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
The journal of physical chemistry. A
|October 8, 2024
概括
碰撞诱导的H++H2反应中的正极变换提供了对寒冷星际环境的洞察. 计算揭示了温度依赖的转换比率,这对于理解太空中的分子至关重要.
科学领域:
- 物理化学 物理化学
- 天体化学是天体化学.
- 量子动力学 量子动力学是什么?
背景情况:
- 在理解星际化学方面,H+ + H2反应是基本的.
- 分子的Ortho-para转换影响其冷却和化学进化在寒冷的环境中.
- 需要精确的速率系数来模拟这些过程在星际介质.
研究的目的:
- 在H++H2反应中计算对正正对比转换的碰撞诱导速率系数.
- 研究低碰撞能量和旋转状态对转换过程的影响.
- 为探测寒冷的星际环境提供数据.
主要方法:
- 在超球坐标中结合的三维 (3D) 时间依赖波束 (TDWP) 形式主义.
- 在H3+的Ab initio地面上,H3+的亚亚巴特潜在能量表面.
- 在低碰撞能量 (0 < E_col ≤ 0.3 eV) 的旋转解决反应概率和截面的计算.
主要成果:
- 对H+ + H2 (v=0,j=0-5) → H+ + H2 (v'=0,j') 得到了汇聚的反应概率和截面.
- 确定了整形到形 (O-P) 和形到整形 (P-O) 转换的速率常数.
- орто-para转换比率与增加的旋转状态趋同,与量子统计方法一致,在较低的温度下达到峰值.
结论:
- 这项研究为H+ + H2正位对位转换提供了准确的碰撞诱导速率系数.
- 计算的比率为冷恒星间环境的寿命提供了洞察力.
- 转换比率的低温峰值归因于特定的旋转状态过渡.
相关概念视频
Hybridization of Atomic Orbitals II
31.9K
sp3d and sp3d 2 Hybridization
31.9K
Hybridization of Atomic Orbitals I
46.6K
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
46.6K
ortho–para-Directing Deactivators: Halogens
5.4K
Halogens are ortho–para directors. They are more electronegative than carbon. Therefore, as ring substituents, they can withdraw electrons through the inductive effect and deactivate the aromatic ring towards electrophilic substitution. Halogens also have an electron-donating resonance effect on the ring, which influences the orientation of the incoming electrophile. If an electrophile attacks at the ortho or the para position, the halogen donates electrons and stabilizes the intermediate...
5.4K
Hess's Law
44.6K
There are two ways to determine the amount of heat involved in a chemical change: measure it experimentally, or calculate it from other experimentally determined enthalpy changes. Some reactions are difficult, if not impossible, to investigate and make accurate measurements for experimentally. And even when a reaction is not hard to perform or measure, it is convenient to be able to determine the heat involved in a reaction without having to perform an experiment.
44.6K
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
5.9K
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
5.9K
The Bohr Model
51.5K
Following the work of Ernest Rutherford and his colleagues in the early twentieth century, the picture of atoms consisting of tiny dense nuclei surrounded by lighter and even tinier electrons continually moving about the nucleus was well established. This picture was called the planetary model since it pictured the atom as a miniature “solar system” with the electrons orbiting the nucleus like planets orbiting the sun. The simplest atom is hydrogen, consisting of a single proton as...
51.5K


