The
polarization data has been analysed using two different approaches.
The equations relating the intensity and the input polarisation angle
are ^{21}
I_{s} = C sin 2γ ^{2}(3)
I_{p} = A cos^{2}γ + B sin^{2}γ ^{2}(4)
I_{45} = A cos^{2}γ + B sin^{2}γ +C sin 2γ^{2} (5)
Where:
A = a_{2} χ_{xzx}+ a_{3} χ_{zxx}+ a_{4} χ_{zzz}(6)
B = a_{5} χ_{zxx} (7)
C = a_{1} χ_{xzx} (8)
The a_{i}
coefficients are combinations of Fresnel factors, which using a
3layer model (air, interface and water) take into account the
dependence on the refractive indices of the phases and the angle of
incidence of the fundamental and ?reflected angle? of the second
harmonic wavelength^{22}.
The parameters used in this work are given in table 2. At this stage
the value of the interfacial refractive index, n_{int},
was assumed to be the average value of the bulk media refractive
indices, n_{air} and n_{water}. This
gives a value of n_{int}=1.167.
n

a_{1}

a_{2}

a_{3}

a_{4}

a_{5}

a_{6}

1.167

0.25

0.22

0.12

0.15

0.19

0.25

Table
2: The a_{i }coefficients derived for benzo15crown5 