The spin' function of a free particle, in the basis in which s_z is diagonal can be written as \[\left[ {\begin{array}{*{20}{c}} 1 \\ 0 \end{array}} \right]\] and \[\left[ {\begin{array}{*{20}{c}} 0 \\ 1 \end{array}} \right]\] with eigen values \[ + \frac{\hbar }{2}\] and \[ - \frac{\hbar }{2}\] respectively. In the given basis, the normalized eigen function of s_y with eigen value \[ - \frac{\hbar }{2}\] is