Calculation of Intensity of of AX crystals

In summary, the author is still confused on using the equation about atomic scattering factor, f = a*e^(-b+((sin(theta)/lamda)^2) + c (general equation), where sin(theta)/lamda = 1/2d = 1/(2*(sqrt(a^2/(h^2 + k^2 +l^2)))), so this term is dependent on the plane. which you will used to find the Intensity of crystals in a certain plane. I = F^2 (disregard multiplicity factor, absorption and etc.), F = f*cos(2pi(hx + ky + lz))
  • #1
ralden
85
0
I'm still confuse on using the equation about atomic scattering factor, f = a*e^(-b+((sin(theta)/lamda)^2) + c (general equation),

where sin(theta)/lamda = 1/2d = 1/(2*(sqrt(a^2/(h^2 + k^2 +l^2)))), so this term is dependent on the plane.
which you will used to find the Intensity of crystals in a certain plane. I = F^2 (disregard multiplicity factor, absorption and etc.), F = f*cos(2pi(hx + ky + lz)) (i omitted the isine part)

so given a compound NaCl where a, b and c are also given, i try to so solve I in 111 plane.

first i solve fNa and fCl using the equation above, this gives 26.30, and 23.71 respectively, and substitute to the equation of intensity i got I(NaCl)=106.44, but when I'm try to check using related literature, some website (http://pd.chem.ucl.ac.uk/pdnn/diff2/structf.htm) and its jcpds, my answer was wrong so please enlighten me about this matter.

constant i used:
for Na:
a1Na=3.2565;b1Na=2.6671;a2Na=23.9362;b2Na=6.1153;a3Na=1.3998;b3Na=0.2001;a4Na=1.0032;b4Na=14.039;c1Na=0.404;
for Cl:
a1Cl=18.2915;b1Cl=0.0066; a2Cl=17.604; b2Cl=1.1717;a3Cl=6.5337;b3Cl=19.5424;a4Cl=2.3386;b4Cl=60.4486;c1Cl=-16.378;
 
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  • #2
The formula for the atomic (or ionic) scattering factor given here

http://scripts.iucr.org/cgi-bin/paper?sh0059

is

[itex]
f(s) = \sum\limits_{i=1}^{4}a_i \exp(-b_i s^2) +c \\
s = \sin(\theta)/\lambda = Q/4\pi = 1/2d
[/itex]

(you have a "+" which is probably a typo)

You should use the scattering factors for the ions, Na+ and Cl-

The constants given in the paper look a bit different from yours, but I have not checked every one of them.
 

1. What is the intensity of AX crystals and how is it calculated?

The intensity of AX crystals is a measure of the brightness or amplitude of the diffraction pattern produced by the crystal. It is calculated using the formula I = |F|^2, where I is the intensity and F is the structure factor.

2. What factors affect the intensity of AX crystals?

The intensity of AX crystals is affected by several factors, including the crystal's structure, the orientation of the crystal with respect to the incident beam, the wavelength of the incident radiation, and the number of unit cells in the crystal.

3. How is the structure factor (F) of AX crystals determined?

The structure factor (F) of AX crystals is determined using X-ray crystallography techniques, which involve analyzing the diffraction pattern produced by the crystal. The positions and intensities of the diffraction peaks are used to calculate the structure factor.

4. Can the intensity of AX crystals be used to determine the crystal's structure?

Yes, the intensity of AX crystals can be used, along with other data such as the wavelength of the incident radiation and the orientation of the crystal, to determine the crystal's structure. This is known as crystal structure analysis.

5. How does the intensity of AX crystals relate to their physical properties?

The intensity of AX crystals is related to their physical properties, such as their density and atomic arrangement. By analyzing the intensity of diffraction peaks, scientists can gain insight into the crystal's physical properties and use this information for various applications, such as in materials science and drug development.

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