Sam - PXRD Flashcards
1
Q
what is the wavelength?
A
distance between two peaks
2
Q
what is theta?
A
angle between incident and diffracted wave
3
Q
what is path difference for constructive interference?
A
n x wavelength (n=1 so just wavelength)
4
Q
constructive v destructive interference
A
destructive = where the path length isnt an integer no. of wavelengths
5
Q
why do systematic absences occur?
A
because of destructive interference of reflections from certain planes, or other translational symmetry elements
6
Q
equation for body centred miller indices to be allowed in diffraction pattern
A
h+k+l = 2n
7
Q
equation for face centred miller indices to be allowed in diffraction pattern
A
h,k,l all odd or all even
