2.4 The Static Dielectric Constant
69
Table 2.4 Static dielectric constant, (0), of some materials
Substance
(0)
Potassium tantalite niobate (KTN)
6000
Barium titanate (BaTiO 3 )
4000
Potassium niobate (KNbO 3 )
700
Strontium titanate (SrTiO 3 )
300
Water
80
Titanium dioxide (TiO 2 )
50
Acetone (C 3 H 6 O)
20
Silicon (Si)
12
GaAs
11
Soda–lime glass
7
KCl
5
Fused silica (SiO 2 )
4
Epoxy
4
PVC
3.5
Teflon
2
Paraffin
2
Air
1.0006
determines the solvation ability, and is used as a dielectric reference standard. Most
importantly, however, is that it allows us to understand the molecular dynamics of
water, because the causality principle and Kramers–Kronig relations (2.10), (2.11)
associate (0) with dielectric losses, which is represented by the imaginary part
of the dielectric function (
(ω)), the main part of which is the Debye relaxation
associated with molecular dynamics. The Debye relaxation makes up to 95% of the
static dielectric constant of water.
8 Thus, the problems of the dielectric relaxation
interpretation (see Sect. 2.3) are automatically transferred to the dielectric constant,
and vice versa.
Figure 2.8 shows the experimental temperature dependencies of the static dielectric constant of water and ice. Malmberg et al. [24] and Johari et al. [25] showed
that these curves are described by the formulas w (0) = 87.740–0.40008·t
◦ +
9.398·10
−4
· t
◦2 –1.410·10
−6
· t
◦3 for water and I (0) = 3.2 + (24620)/(t
◦ +266.8) for
ice, where t
◦ is temperature in
◦ C. It can be seen from the figure that the difference
between the values of (0) near 273 K for water and ice is less than 10%, and that
except of this slight shift, which is apparently due to the density difference (see the
solid lines and the right-hand scale), the curves generally show a uniform trend.
9
8 The same is true for alcohols (see, for instance, [21]).
9 This is despite the fact that the relaxation time changes by seven orders of magnitude (see Chap. 4
for details).
69
Table 2.4 Static dielectric constant, (0), of some materials
Substance
(0)
Potassium tantalite niobate (KTN)
6000
Barium titanate (BaTiO 3 )
4000
Potassium niobate (KNbO 3 )
700
Strontium titanate (SrTiO 3 )
300
Water
80
Titanium dioxide (TiO 2 )
50
Acetone (C 3 H 6 O)
20
Silicon (Si)
12
GaAs
11
Soda–lime glass
7
KCl
5
Fused silica (SiO 2 )
4
Epoxy
4
PVC
3.5
Teflon
2
Paraffin
2
Air
1.0006
determines the solvation ability, and is used as a dielectric reference standard. Most
importantly, however, is that it allows us to understand the molecular dynamics of
water, because the causality principle and Kramers–Kronig relations (2.10), (2.11)
associate (0) with dielectric losses, which is represented by the imaginary part
of the dielectric function (
(ω)), the main part of which is the Debye relaxation
associated with molecular dynamics. The Debye relaxation makes up to 95% of the
static dielectric constant of water.
8 Thus, the problems of the dielectric relaxation
interpretation (see Sect. 2.3) are automatically transferred to the dielectric constant,
and vice versa.
Figure 2.8 shows the experimental temperature dependencies of the static dielectric constant of water and ice. Malmberg et al. [24] and Johari et al. [25] showed
that these curves are described by the formulas w (0) = 87.740–0.40008·t
◦ +
9.398·10
−4
· t
◦2 –1.410·10
−6
· t
◦3 for water and I (0) = 3.2 + (24620)/(t
◦ +266.8) for
ice, where t
◦ is temperature in
◦ C. It can be seen from the figure that the difference
between the values of (0) near 273 K for water and ice is less than 10%, and that
except of this slight shift, which is apparently due to the density difference (see the
solid lines and the right-hand scale), the curves generally show a uniform trend.
9
8 The same is true for alcohols (see, for instance, [21]).
9 This is despite the fact that the relaxation time changes by seven orders of magnitude (see Chap. 4
for details).