Relative stability of naphthalene, quinoline and isoquinoline under high energy electron impact

- High voltage fast switching circuit is developed to implement delayed extraction time of flight mass spectrometry technique.
- Slow and fast dissociation channels are separated using delayed extraction technique and decay time constants are estimated.
- High energy electron impact in PAHs and PANHs is probed particularly in the context of astronomical and astro-biological significance.
- Acetylene/HCN evaporation process is investigated for statistical dissociation due to plasmon excitation.

Stability of naphthalene and two of its nitrogen containing derivatives namely, quinoline and isoquinoline are investigated under high energy electron impact. Astro-biologically important statistical dissociation channels are probed using the delayed extraction time-of-flight mass spectrometry technique. The experimental configuration was designed to avoid yield variation due to the thermal velocities for 5 μs or more after the collision. The statistical decay channels show an increase in the yield of daughter ions as a function of extraction delay in the range of 106 s−1. On the other hand, the yields due to fast dissociation channels were observed to decrease as a function of extraction delay. On the basis of projectile beam energy dependence of the yields, the effect of plasmon excitation in quinoline and isoquinoline is shown for the first time. A strong dependence of the statistical dissociation yield on the location of the nitrogen atom in the two molecules is observed. An attempt is made to correlate these observations with the various structure parameters obtained using structure calculations.

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