What is different about what happens to excited electrons in the photopigment in the reaction center

1) What is different about what happens to excited electrons in the photopigment in the reaction center, compared with those of other photopigments in the antenna complex?

2) Where, precisely, does the oxygen released in photosynthesis come from? Some bacteria are autotrophs, but in place of water they utilize H2S. In other words, they use H2S in exactly the same way that green plants use water. Do these bacteria release molecular oxygen as a waste product? Explain why or why not.