X-RA YS AND ORIENTA TION OF QUARTZ CRYSTALS 337 



normal to the atomic plane (2T-v3) in terms of the reference edges of the 

 slab after rotations Ji and A2 (See Fig. 3.30). These are 



/-.0966\ 



N = f -.9919) 



\- .0830/ 



Substituting in equation (3.26) 



^^"^ '' = :99i9- 



5; = -4°48' 



and in equation (3.29) 



^ / -.0966 

 tan 62 = 



-.9919 

 So = 5'35' 

 and from equations (3.25), (3.28), (3.31), and (3.35): 



gx = 27°25' 

 g-i = 37°45' 



gz = 2>rv 



gi = 26°35' 



which are the g angles for X-raying the XT slab where the reference edge 

 is the intersection between the slab-surface and the Z-section surface. 



