# The sign of Schrodinger equation

I have a question for the format of Schrodinger equation

$$\psi(x,t) = \int_0^\infty c_n e^{-iE_nt/\hbar} \psi_n(x)$$

Why do we have $i$ instead of $-i$?

• It is a matter of convention for the Fourier transform more generally, not just the Schrödinger equation, I think your question is already answered here: physics.stackexchange.com/q/308234 – Kirill Sep 5 '18 at 17:04