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A comparison of femtosecond and nanosecond multiphoton ionization and dissociation for some nitro‐molecules
Author(s) -
Ledingham Kenneth W. D.,
Deas Robert M.,
Marshall Archibald,
McCanny Thomas,
Singhal Ravi P.,
Kilic Hamdi S.,
Kosmidis Costantine,
Langley Andrew J.,
Shaikh Waseem
Publication year - 1995
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1290091512
Subject(s) - chemistry , mass spectrometry , nanosecond , ionization , mass spectrum , fragmentation (computing) , femtosecond , molecule , ion , polyatomic ion , dissociation (chemistry) , photoionization , infrared multiphoton dissociation , resonance enhanced multiphoton ionization , analytical chemistry (journal) , laser , optics , organic chemistry , chromatography , physics , computer science , operating system
Resonance‐enhanced multiphoton ionization spectrometry (REMPI), using time‐of‐flight mass spectrometers and tuned lasers, has proved an important ultra‐sensitive analytical technique. Nevertheless, conventional nanosecond REMPI suffers from a number of shortcomings: most importantly, REMPI often fails through rapidly (pre)dissociating states. In the case of thermally labile molecules, which include the nitro‐molecules, either no or very small parent or high/mass fragment ion peaks exist, making the interpretation of the mass spectra ambiguous at best and often impossible. Femtosecond laser mass spectrometry (FLMS) can often ‘defeat’ these dissociative states, resulting in large parent or high‐mass fragment ion peaks which make the interpretation less ambiguous. In the present paper, nanosecond and femtosecond multiphoton ionization and fragmentation are compared using time‐of‐flight mass spectrometry for NO 2 gas and a number of different nitro‐molecules: nitromethane, nitrobenzene, m ‐nitrotoluene, dinitrotoluene and trinitrotoluene.