Vacuum Ultraviolet and Infrared Spectra of Condensed Methyl Acetate on Cold Astrochemical Dust Analogs

Abstract

The Open University's repository of research publications and other research outputs Vacuum ultraviolet and infrared spectra of condensed methyl acetate on cold astrochemical dust analogs

Electron impact dissociation of amorphous cis-methyl acetate ice analogs

“…IR spectra recorded after deposition showed several bands corresponding to fundamental, combination and overtone vibrational modes of CH 3 COOCH 3 ice at 85 K. In addition to those vibrational bands observed by Sivaraman et al [6], in this experiment we covered the 800-500 cm À1 region and observed two new bands at 606 cm À1 and 650 cm À1 (Figure 2a) that corresponds to 2m 17 and m 15 , respectively. Several other new bands appeared in the spectra between 1890 cm À1 and 2850 cm À1 region ( Figure 2b) and are listed in Table 1 (Table 1).…”

“…Though several new bands appeared in the spectra by depositing CH 3 COOCH 3 molecules at 85 K, we found no match between the suggested band positions for trans-CH 3 COOCH 3 molecule by Senent et al [7]. Instead, the recorded IR spectra was found to be in good agreement with the band positions reported by Sivaraman et al [6] and therefore the icy layers grown by molecular deposition on to the cold substrate, kept at 85 K, was found to contain only cis-CH 3 COOCH 3 molecules.…”

“…In the spectra presented at lower temperatures by Sivaraman et al [6] only the band at 3460.2 cm À1 corresponding to 2m 5 region was observed to show changes upon annealing and at 120 K it was found to have shifted to 3438.7 cm À1 indicating the phase change from amorphous to crystalline phase. Due to the difference in temperature between these two experiments, our data by depositing 2m 17 * Band assignments are from Refs.…”

“…Due to the difference in temperature between these two experiments, our data by depositing 2m 17 * Band assignments are from Refs. [6] and [14]. [11].…”

“…(2)) could be a dominant pathway in synthesizing CH 3 COOCH 3 as all the three molecules were reported to be in the Orion. Following the first identification a detailed vacuum ultraviolet (VUV) and infrared (IR) spectroscopic study was also reported [6] for use in identifying and understanding the chemical nature of the molecule in different regions of the ISM. However, the dissociation of this molecule under astrochemical ice analog conditions are least understood.…”