589 fractal agglomerate, 590 fractal dimension, , 590 fraction, 590 fraction collector in chromatography , 590 fraction extracted, , 591 fractional change of a quantity, 591 fractional selectivity in catalysis, 591 fractionation of analytes , 592 fractionation of polymers , 592 fragment ion in mass spectrometry, 593 fragmentation, 593 fragmentation reaction in mass spectrometry , 594 frame-shift mutation, 594 Franck–Condon principle, 595