Fragmentation of pure nitromethane in the gas phase and a collision-free system at laser interactions of 532 nm, 355 nm, and 266 nm.

High-resolution mass spectrometry using the time of flight (TOF) technique with a reflectron with multiphoton absorption was used to analyze the fragmentation pattern of nitromethane in a collision-free system. We used a radiation source with nanosecond laser pulses of 532 nm, 355 nm, and 266 nm wavelengths and a supersonic jet of nitromethane to produce positive fragment ions. The density power (irradiation) range was from 109 to 1010 W/cm2. The identification of 20 ions at a wavelength of 532 nm was obtained, whereas at 266 nm, more than 60 fragment ions were identified, as was the parent ion and many clusters. We associate these ionic fragments as a function of the intensity, energy, and pulse duration of the radiation source. The observation of radicals such as CH 1,2,3 , C 2 H 1,2,3 , C 3 H 1,2,3 , and CH 3 O, CHNO, higher mass molecules, and clusters is presented. The absence of the parent ion at 532 nm and 355 nm wavelengths demonstrates that the ladder switching mechanism elucidates the dissociation-ionization (DI) pathways of nitromethane. At 266 nm, the presence of the parent ion and the clusters are an indication of the functioning of the other model of fragmentation (ID). Due to the experimental characteristics, the numerous fragments seem to be a result of the interactions of the intensity of the electromagnetic radiation over nitromethane in the gas phase and their clusters. • The experimental settings allow the cluster formation. • At 532 nm the products of the major and minor dissociation paths was identified. • At UV interactions the clusters originate the radicals CH 1,2,3 , C 2 H 1,2,3 , C 3 H 1,2,3. [ABSTRACT FROM AUTHOR]