Carbon isotope effect in superconductingMgCNi3

Carbon Isotope Effect in Single-Crystal Rb3C60

The sharp resistive transitions in superconducting single crystals of natural abundance and 99% 13C-enriched Rb3C60 reveal the carbon isotope effect with unprecedented accuracy. The measured isotope exponent aC 0.21 6 0.012 is outside the error bars of all previous reported values. Our precise value for aC, combined with Tc, aRb , and an ab initio calculation of the frequency distribution of th...

Effect of water regime on carbon isotope composition of lichens.

delta(13)C values of the lichens Ramalina duriaei and Teloschistes villosus collected in their natural habitat were repeatedly measured during 2 years. Results show variations in the stable carbon isotope ratios ((13)C/(12)C). Such variations are correlated to the seasonal rainfall, i.e. low values of delta(13)C of the lichens during the winter and high values of delta(13)C during the dry summe...

Paired positive carbonate carbon isotope, organic carbon isotope, and oxygen isotope composition study across the Lower Mississippian positive carbon isotope excursion, southeastern Nevada, USA

Effect of Carbon Isotope Abundance on Thermal Conductivity and Raman Scattering of Single-Walled Carbon Nanotubes

We have been studying the heat conduction characteristics along a single-walled carbon nanotube (SWNT) by the molecular dynamics method [1-3] with the simplified form [4] of TersoffBrenner bond order potential [5]. Our preliminary results showed that thermal conductivity was strongly dependent on the nanotube length for realistic length scale for device applications [2, 3]. Furthermore, we have...

Isotope Effect in Diffusion

A derivation of the classical jump rate I' for tracer diffusion aimed at a clear expression for the mass dependence of the frequency factor v is presented. The derivation is effected without using the usual collective normal coordinates which usually combine the masses in a complicated way. v depends explicitly on the mass of the surrounding host atoms (as well as on the tracer-atom mass) if th...