Temperature dependence helium clusters

These experimental results for electron detachment from (He) superfluid clusters [99, 242-245] and the present analysis reflect beautifully on the role of electron bubbles as microscopic probes for superfluidity of finite boson quantum clusters. The classical 1960 studies of Meyer and Reif [207] provided direct information on the roton energy from the interrogation of the temperature dependence of the electron mobility in bulk superfluid helium. Our analysis and the experimental results [242-245] enable the interrogation and theoretical exploration of the electron bubble translational motion in the image potential within normal fluid and superfluid clusters, allowing us to infer on the dramatic effects of superfluidity in large finite boson quantum clusters using the techniques of electron detachment. 

For some metal ions, such as high-spin Co° (5=3/2) or iron-sulfur clusters, the electron spin relaxation time is strongly temperature dependent. If the relaxation time becomes too short, then the signal becomes so broad that the signal is essentially undetectable. For many high-spin Co complexes and iron sulfur clusters, detection of an EPR signal requires temperatures in the liquid helium range. 

In helium, at low densities (Af) increases linearly with density before rising rapidly to an approximately constant value, the magnitude of which is dependent upon the temperature of the gas and is characteristic of the particular clustered state. The transition is abrupt in this case, but is shown to be softer for N2 since the rise in (Af) occupies a much broader... 

After about 3 10 y the temperature was about 3 10 K and by combination of nuclei and electrons the first atoms of hydrogen and helium were formed. At further stages of expansion and cooling the first H2 molecules became stable. Due to gravitation, the matter began to cluster and the formation of galaxies and stars began after about 10 y. The further individual development of the stars depended and still depends mainly on their mass. 

---