The time$-$dependent wave function for a particle is given by

$($x$,$ t$)=$ Cei$($kx $$t$)+$ Ce$$i$($kx $+$t$)$

in the range

$$

$32$k

$<$ x $<$

$32$k

$,$

where

k $=2\mathrm{.}63$ nm$1,$

and

$($x$,$ t$)=0$

everywhere else. In the range where the wave function is nonzero, the function consists of two waves of equal amplitude traveling in opposite directions superimposed on each other, resulting in a standing wave. $($This wave function is consistent with that of a particle trapped in a one$-$dimensional box.$)$