( Subsequently ( , ( ( the ( excited electron ) ) ( ( ( ( relaxes ( to ( a ( lower level ) ) ) ) and ) ( ( emits light ) ( in ( ( the form ) ( of ( ( ( a ( lower-energy photon ) ) ( -LRB- ( red -RRB- ) ) ) ( in ( the ( ( visible light ) region ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Subsequently)) (, ,) (NP (DT the) (VBN excited) (NN electron)) (VP (VP (VBZ relaxes) (PP (TO to) (NP (DT a) (JJR lower) (NN level)))) (CC and) (VP (VBZ emits) (NP (NN light)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (NP (NP (DT a) (JJ lower-energy) (NN photon)) (PRN (-LRB- -LRB-) (ADJP (JJ red)) (-RRB- -RRB-))) (PP (IN in) (NP (DT the) (ADJP (JJ visible) (JJ light)) (NN region))))))))) (. .)))
Subsequently, the excited electron relaxes to a lower level and emits light in the form of a lower-energy photon (red) in the visible light region.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS electrons)) (VP (VB return) (PP (TO to) (NP (DT a) (JJR lower) (NN energy) (NN level)))))) (, ,) (NP (PRP they)) (VP (VBP emit) (NP (NP (DT the) (JJ excess) (NN energy)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (NN light))))))) (. .)))