Time evolution of spin state of radical ion pair in microwave field: An analytical solution

The paper reports an exact solution for the problem of spin evolution of radical ion pair in static magnetic and resonant microwave field taking into account Zeeman and hyperfine interactions and spin relaxation. The values of parameters that provide one of the four possible types of solution are analysed. It is demonstrated that in the absence of spin relaxation, besides the zero field invariant an invariant at large amplitudes of the resonant microwave field can be found. The two invariants open the possibility for simple calculation of microwave pulses to control quantum state of the radical pair. The effect of relaxation on the invariants is analysed and it is shown that changes in the high field invariant are induced by phase relaxation.Comment: 18 pages, 7 figure

Fractal formation and ordering in random sequential adsorption

We reveal the fractal nature of patterns arising in random sequential adsorption of particles with continuum power-law size distribution, $P(R)\sim R^{\alpha-1}$, $R \le R_{\rm max}$. We find that the patterns become more and more ordered as $\alpha$ increases, and that the Apollonian packing is obtained at $\alpha \to \infty$ limit. We introduce the entropy production rate as a quantitative criteria of regularity and observe a transition from an irregular regime of the pattern formation to a regular one. We develop a scaling theory that relates kinetic and structural properties of the system.Comment: 4 pages, RevTex, 4 postscript figures. To appear in Phys.Rev.Let

Effect of implantation of high-energy Ne ions on the structure of aluminium-manganese alloy

Translated from Russian (Fiz. khim. obrab. mater. 1998 (1) p. 5-8)Available from British Library Document Supply Centre-DSC:9023.190(9841)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Evolution of the microstructure of ageing aluminium alloys in high-energy ion implantation

It is well-known that the radiation defects, formed during ion implantation, have a strong effect on the structural-phase condition of the metals and alloys and change of the properties. In previous work, we carried out investigations of the changes of the structure and properties of thermally non-hardened alloys of the system Al-Mn (AMts) implanted with high-energy Ne ions. In this work, these investigations were continued for thermally hardened alloys, i.e. ageing aluminium alloysTranslated from Russian (Fiz. Khim. Orab. Mater. 1998 32(6) p. 9-14)Available from British Library Document Supply Centre-DSC:9023.190(10169)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo