Director Reorientation in Smectic

Prom these observations and equations (6.205) and (6.206) it follows that 

Taking the scalar product of (6.312) with a and c gives, respectively, 

Multiplying (6.315) by sin0 and (6.316) by cos0 and subtracting the resulting equations then eliminates r and yields the governing d3mamic equation 

In the special one-constant approximation B = B2 = B this equation reduces to 

This dynamic equation and simplified versions of it, arising from alternative derivations, occur frequently in the fiterature on SmC liquid crystals, as will be discussed 

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