Light hits the chlorophyll, it takes on energy and moves to a higher
energy state.
An electron acceptor, Ferredoxin, carries them to a carrier system
which contains 3 enzymes.
As they move through this system, the energy the electrons are carrying
is slowly released to turn 2ADP's and 2
into 2 x ATP's
which are fed into the Dark Phase.
When the electron reaches the 3rd carrier enzyme it has lost all
its extra energy and is brought back to the ground state. It is now
ready to take on light energy again and repeat the process.