## BRAGGS' EQUATION

BRAGGS' EQUATION allows a number of different simple uses of Braggs' equation. From known angles and wavelength (or energy), the corresponding d-spacings may be calculated using the D-SPACING sub-menu option. From known d-spacings and wavelength the corresponding angles may be calculated using the TWO THETA ANGLE option. From known d-spacings and angles the wavelength (and photon energy) may be calculated using WAVELENGTH/ENERGY . The commands EXIT or QUIT can be used to return to the main menu.

Here is an example of use, which converts a angle at one wavelength into the equivalent diffraction peak angle at a different wavelength:

Main menu: ENTER COMMAND [INPUT DATA]:bragg
Bragg equation sub-menu: ENTER COMMAND [D-SPACING]:
WAVELENGTH (Angstroms) (0.0 for keV )
(Range: 0.0 to 1.000E+05) [1.54061]:
INFO: Energy =    8.047779     keV
TWO THETA ANGLE (Degrees) (Range: 0.0 to 180.000) [20.0000]:69.79
INFO: D-spacing (Angstroms) =      1.34652
Bragg equation sub-menu: ENTER COMMAND [TWO THETA ANGLE]:
WAVELENGTH (Angstroms) (0.0 for keV )
(Range: 0.0 to 1.000E+05) [1.54061]:0.
ENERGY OF RADIATION (keV) (Range: 1.000E-03 to 10000.0)
[8.04778]:16.5
INFO: Wavelength =    .7514255     Angstroms
D-SPACING (Angstroms) (Range: 1.000E-03 to 1.000E+06)
[1.34652]:
INFO: Two theta angle (Degrees) =     32.40415
Bragg equation sub-menu: ENTER COMMAND [D-SPACING]:exit


Andrew Hammersley
2004-01-09