Hiroko Kaji

Hindered rotation of the PF3Ru(001) surface system as a classical gear network

Abstract Rotational motion of PF 3 molecules adsorbed on Ru(001) is hindered by other molecules adsorbed on near-neighbor sites. In the limit of very strong hindrance of rotation, a neighboring molecule pair is considered to rotate like gears engaged with each other. The distribution of azimuthal orientation is obtained with the gear network model. The temperature- and coverage-dependence of the angular distribution agrees qualitatively with the results of ESDIAD measurements.

Theoretical analysis of coverage-dependent rotational hindrance of PF3 adsorbed on Ru(001)

Distribution of the azimuthal orientation of PF 3 molecules adsorbed on Ru(001) measured by ESDIAD shows interesting temperature and coverage dependences. It is interpreted in this analysis as due to the short range order in the locative distribution of the PF 3 molecules. Monte Carlo simulations are performed to obtain the temperature and coverage-dependent distribution of the adsorbed molecules. The distribution of the azimuthal orientation of the molecule is discussed on the basis of the obtained locative distribution of the molecules by using simple models for rotational hindrance to be compared with the experimental results.

Adsorbed PF3 on Ru(001) — Quantum Gear Problem?

According to the recent ESDIAD experiment PF3 molecules adsorbed on Ru(001) show interesting coverage- and temperature-dependent rotational hindrance. A model is constructed that the molecules sit on the atop site, having short ranged interactions. The analysis is made by using Monte Carlo simulation. On the obtained distributions, rotational motions of isolated adsorbates and adsorbate clusters are discussed quantum-mechanically. A possible quantum gear like situation is found for the adsorbate clusters.

Rotational motion of PF3 gear network on Ru(001) surface

The angular distribution of PF3 molecules adsorbed on Ru(0 0 1) surface is studied with use of Monte Carlo simulation. The rotational motion of the molecules is treated as gears engaged to each other. The coverage dependence of the angular distribution of the molecules such as that observed by electron stimulated desorption ion angular distribution can be explained by considering the coupling between the lateral distribution of PF3 molecules and their rotational motion.

Atomic displacements and electronic properties for 4 ? 1?8 ? 2 phase transition of In-adsorbed Si(111) surface

The In-adsorbed Si(111) 4×1 reconstructed surface is known to undergo a phase transition to an 8×2 structure at approximately 130 K. This structural transition accompanies a metal-insulator transition known as the Peierls transition or charge density wave (CDW) transition. We construct a continuous displacement model and discuss the surface electronic states using a tight-binding model based on the first principles calculations. We performed Monte Carlo simulations, estimated the atomic displacement, and calculated the surface electronic properties around the transition temperatures, in terms of the density of states projected into the reciprocal space (RDOS). The results show that the nature of the transition can be understood as the order-disorder transition of an Ising system.