Low temperature chemistry and physics in superfluid 4He
- Experimental and theoretical research of chromophore - superfluid
bath dynamics
- Synthesis of new nanomaterials in superfluid helium
- Experimental methods include laser excitation spectroscopy,
fluorescence and
absorption spectroscopy from VUV to IR
- Density functional theory and quantum Monte Carlo modeling of
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).
Back to the main page.