Condensed Matter Physics, 2006, vol. 9, No. 4(48), p. 703708, English
DOI:10.5488/CMP.9.4.703
Title:
A microscopic theory of
photonucleation: Density functional approach to the properties of
a fluid of twolevel atoms, a part of which is excited
Author(s):
 O.Derzhko
(Institute for Condensed Matter Physics of the National
Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011
Lviv, Ukraine)
,

 V.Myhal
(The Ivan Franko National University of
L'viv, Department for Theoretical Physics, 12 Drahomanov Street,
79005 L'viv, Ukraine)

We use the density functional method
to examine the properties of the nonuniform (twophase) fluid of twolevel atoms,
a part of which is excited.
From the analysis of the equation of state of a gas of twolevel atoms,
a part of which is excited,
the following density functional of the grand thermodynamical potential emerges
Ω[ρ(r)] =Ω_{CS}[ρ(r)]
6σ^{3}a(c_{1},T)π^{1}
∫_{r1r2≥
2σ}dr_{1}dr_{2}
ρ(r_{1})ρ(r_{2})r_{1}{\bf{r}}_2^{6}
with
a(c_{1},T)
=32^{1}a^{2}v(E_{1}E_{0})
(c_{0}c_{1}+2c_{0}c_{1}E_{1}E_{0}[kT]^{1})
(here Ω_{CS}[ρ(r)] is the
CarnahanStarling term, σ is the atom radius,
v=4/3πσ^{3}, c_{1} is the concentration of excited
atoms, c_{0}+c_{1}=1, E_{1}E_{0} is the excitation energy and a is
the dimensionless parameter which characterizes the atom). We use
this expression to calculate the nucleation barrier for
vaportoliquid phase transition in the presence of excited atoms.
Key words:
photonucleation,
nucleation barrier,
density functional approach
PACS:
64.70.Fx, 82.65.Dp, 62.60.Nh, 64.60.Qb
