( Fluorescence ( ( is ( ( the phenomenon ) ( ( by which ) ( ( certain materials ) ( ( ( absorb ( ultraviolet energy ) ) and ) ( ( re-emit ( this ( invisible radiation ) ) ) ( in ( ( the form ) ( of ( visible ( colored light ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Fluorescence)) (VP (VBZ is) (NP (NP (DT the) (NN phenomenon)) (SBAR (WHPP (IN by) (WHNP (WDT which))) (S (NP (JJ certain) (NNS materials)) (VP (VP (VB absorb) (NP (JJ ultraviolet) (NN energy))) (CC and) (VP (VB re-emit) (NP (DT this) (JJ invisible) (NN radiation)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (JJ visible) (JJ colored) (NN light))))))))))) (. .)))
Fluorescence is the phenomenon by which certain materials absorb ultraviolet energy and re-emit this invisible radiation in the form of visible colored light.
(ROOT (S (NP (DT The) (JJ light-producing) (NN process) (NN fluorescence)) (VP (VBZ occurs) (SBAR (WHADVP (WRB when)) (S (NP (DT a) (NN substance)) (VP (VP (VBZ absorbs) (NP (JJ shorter-wavelength) (JJ ultraviolet) (NN light))) (CC and) (VP (ADVP (RB then)) (VBZ gives) (PRT (RP off)) (NP (NP (DT the) (NN energy)) (PP (IN as) (NP (JJ visible) (NN light))))))))) (. .)))