Innermost stable circular orbits around magnetized rotating massive stars

In 1998, Shibata and Sasaki [Phys. Rev. D 58, 104011 (1998)] presented an approximate analytical formula for the radius of the innermost stable circular orbit (ISCO) of a neutral test particle around a massive, rotating and deformed source. In the present paper, we generalize their expression by including the magnetic dipole moment. We show that our approximate analytical formulas are accurate enough by comparing them with the six-parametric exact solution calculated by Pach\'on et. al. [Phys. Rev. D 73, 104038 (2006)] along with the numerical data presented by Berti and Stergioulas [MNRAS 350, 1416 (2004)] for realistic neutron stars. As a main result, we find that in general, the radius at ISCO exhibits a decreasing behavior with increasing magnetic field. However, for magnetic fields below 100GT the variation of the radius at ISCO is negligible and hence the non-magnetized approximate expression can be used. In addition, we derive approximate analytical formulas for angular velocity, energy and angular momentum of the test particle at ISCO.Comment: 8 pages, 3 figure

Interlayer energy transfer between carbazole and two 9-anthroyloxy derivatives in Langmuir-Blodgett films

The interlayer excitation energy transfer between 11-(9-carbazole)undecanoic acid (II-CU) and two 9-anthroyloxy derivatives, 9-(9-anthroyloxy)stearic acid (9-AS) and 2-(9-anthroyloxy)stearic acid (2-AS), in alternating multilayer Langmuir-Blodgett films has been studied. The 11-CU fluorescence is quenched by energy transfer to 9-AS or 2-AS as judged by steady-state and picosecond time-resolved fluorescence measurements. The fluorescence decay curves of 11-CU in the films were analyzed in the framework of several models: (1) a general model for interlayer energy transfer, (2) a two-exponential decay, (3) a Forster model for energy transfer in a two-dimensional system, and (4) a stretched-exponential decay, characteristic of Forster energy transfer in self-similar fractal-like structures. The recovered decay parameters suggest an inhomogeneous mixing of the acceptor molecules in LB films leading to a two-phase system. The phase separation during compression of the acceptor monolayers forms regions of acceptor concentration about 3 times that of the intended and regions with very low acceptor concentration

Interlayer energy transfer between carbazole and two 9-anthroyloxy derivatives in Langmuir-Blodgett films

The interlayer excitation energy transfer between 11-(9-carbazole)undecanoic acid (II-CU) and two 9-anthroyloxy derivatives, 9-(9-anthroyloxy)stearic acid (9-AS) and 2-(9-anthroyloxy)stearic acid (2-AS), in alternating multilayer Langmuir-Blodgett films has been studied. The 11-CU fluorescence is quenched by energy transfer to 9-AS or 2-AS as judged by steady-state and picosecond time-resolved fluorescence measurements. The fluorescence decay curves of 11-CU in the films were analyzed in the framework of several models: (1) a general model for interlayer energy transfer, (2) a two-exponential decay, (3) a Forster model for energy transfer in a two-dimensional system, and (4) a stretched-exponential decay, characteristic of Forster energy transfer in self-similar fractal-like structures. The recovered decay parameters suggest an inhomogeneous mixing of the acceptor molecules in LB films leading to a two-phase system. The phase separation during compression of the acceptor monolayers forms regions of acceptor concentration about 3 times that of the intended and regions with very low acceptor concentration