( ( Line ( spectrum ( Spectral lines ) ) ) ( ( are ( produced ( by ( transitions ( of ( electrons ( within ( ( atoms or ) ions ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Line) (NN spectrum) (NN Spectral) (NNS lines)) (VP (VBP are) (VP (VBN produced) (PP (IN by) (NP (NP (NNS transitions)) (PP (IN of) (NP (NP (NNS electrons)) (PP (IN within) (NP (NNS atoms) (CC or) (NNS ions))))))))) (. .)))
Line spectrum Spectral lines are produced by transitions of electrons within atoms or ions.
(ROOT (S (NP (DT The) (NN spectrum)) (VP (VBZ is) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (NP (JJ discrete) (NNS lines)) (VP (VBG representing) (NP (NP (NNS transitions)) (PP (IN of) (NP (NP (DT the) (NN hydrogen) (NN electron)) (PP (IN between) (NP (JJ specific) (NN energy) (NNS levels)))))) (PP (IN within) (NP (DT the) (NN atom)))))))) (. .)))