My lab

Low temperature chemistry and physics in superfluid
4He





Research


Superfluid 4He provides a unique medium for carrying out chemistry at very low temperatures (T < 2.1 K). It has unusual properties (liquid down to 0 K, vanishing viscosity, and super-thermal conductivity), which make it an ideal medium for: carrying out high-resolution molecular spectroscopy, studying coupled chromophore – bath dynamics, synthesis of unusual chemical species, and studying intercalation properties and dynamics of nanomaterials. Results from this research can be used, for example, in synthesizing highly energetic nitrogen compounds (up to 10 kJ/g) or in devloping new nanomaterials. Overall, this research consists primarily of basic research with possible applications toward development of new high-energy fuels and nanomaterial research.

Demonstrations

Time-dependent density functional theory simulation of electron thermalization in superfluid 4He ("bubble expansion").

Experimental visualization of normal (He-I) to superfluid (He-II) phase transition (2.1 K).

Experimental visualization of self-purification of superfluid helium (e.g. clustering of N2 gas molecules in the liquid; "snowfall").

Collaboration

Department of chemistry, Prof. V. A. Apkarian (University of California at Irvine)

Matrix isolation laboratory, Prof. H. Kunttu (University of Jyväskylä)

Representative publications

J. Eloranta and V. A. Apkarian, A time dependent density functional treatment of superfluid dynamics: Equilibration of the electron bubble in superfluid 4He, Journal of Chemical Physics 117, 10139 (2002).

T. Kiljunen, L. Lehtovaara, H. Kunttu, and J. Eloranta, Solvation of triplet Rydberg states of molecular hydrogen in superfluid helium, Physical Review A 69, 012506 (2004)

J. Eloranta, H. Ye. Seferyan, and V. A. Apkarian, Time-domain analysis of electronic spectra in superfluid 4He, Chemical Physics Letters 396, 155 (2004).

V. Ghazarian, J. Eloranta, and V. A. Apkarian, Toward a universal molecule injector in liquid helium: Pulsed cryogenic doped helium droplet source, Review of Scientific Instruments 73, 3606 (2002).

E. A. Popov, J. Eloranta, J. Ahokas, and H. Kunttu, On the formation mechanism of impurity-helium solids: evidence for extensive clustering, Low Temperature Physics 29, 510 (2003).


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