团簇液-气相变的动力学研究

Kinetic energy deposited into a nanodroplet, cluster, or molecule in a sticking collision with background gas

In processes when particles such as nanodroplets, clusters, or molecules move through a dilute background gas and undergo capture collisions, it is often important to know how much translational kinetic energy is deposited into the particles by these pick-up events. For sticking collisions with a Maxwell-Boltzmann gas, an exact expression is derived which is valid for arbitrary relative magnitudes of the particle and thermal gas speeds.

Kinetically Trapped Liquid-State Conformers of a Sodiated Model Peptide Observed in the Gas Phase

We investigate the peptide AcPheAla5LysH+, a model system for studying helix formation in the gas phase, in order to fully understand the forces that stabilize the helical structure. In particular, we address the question of whether the local fixation of the positive charge at the peptide's C-terminus is a prerequisite for forming helices by replacing the protonated C-terminal Lys residue by Ala and a sodium cation. The combination of gas-phase vibrational spectroscopy of cryogenically cooled ions with molecular simulations based on density-functional theory (DFT) allows for detailed structure…

正己烷在气相和液相中的Gamma-ray光谱

Gamma-ray spectra of hexane in gas phase and liquid phase

计算了分子己烷的理论γ射线谱，并与气相（Surko等，1997）和液相（Kerr等，1965）的实验结果进行了比较。本研究揭示了在气相中，并非所有正己烷的价电子都表现出相同的湮灭正电子的几率。只有价空间中的亲正电子占主导地位的伽马射线光谱，这是在气相测量的良好协议。然而，当己烷被限制在液相中时，分子间的相互作用最终消除了气相中的自由分子取向和对亲正电子的选择性。结果表明，正己烷的γ射线谱是所有价电子的平均贡献，这与液相测量结果一致。本文首次认识到亲正电子在正己烷气液两相湮灭过程中的作用。