Functional Group Dependent Site Specific Fragmentation of Molecules by Low Energy Electrons

Abstract

Functional group dependence is observed in the dissociative electron attachment (DEA) to various organic molecules in which the DEA features seen in the precursor molecules of the groups are retained in the bigger molecules. This functional group dependence is seen to lead to site-selective fragmentation of these molecules at the hydrogen sites. The results are explained in terms of the formation of core-excited Feshbach resonances. The results point to a simple way of controlling chemical reactions as well as interpreting the DEA data from bigger biological molecules.

Computation of electron-impact rotationally elastic total cross sections for methanol over an extensive range of impact energy (0.1 – 2000 eV)

“…In the present calculation, the 2A state shows a prominent structure at 8.5 eV, which is in agreement with the earlier predicted values of 8.81 eV [3], 7.9 eV [48], and 8.0 eV [49]. Similarly, another structure is seen in the 2A state at 10.57 eV, which is in agreement with earlier reported values of 11.71 eV [3], 10.5 eV [48], and 10.2 eV [49], which can be visualized as a peak around 11 eV in the TCS curve. It is to be noted that as more states are included in the close-coupling (CC) expansion and retained in the outer region calculation, the eigenphase sum increases, reflecting the improved modeling of the polarization interaction.…”

“…A resonance with 2A symmetries was located at 6.4 eV by Skalicky and Allan [48], at 6.5 eV by Prabhudesai et al [49], and calculated by Bouchiha et al [3] to lie at 6.75 eV. A second resonance with 2A symmetries was identified at 7.9 eV by Skalicky and Allan [48], 8 eV by Prabhudesai et al [49], and calculated by Bouchiha et al [3] to be at 8.81 eV, and a third resonance with 2A symmetry was found around 10.5 eV by Skalicky and Allan [48], 10.2 eV by Prabhudesai et al [49], and calculated by Bouchiha et al [3] to be at 11.73 eV [3]. Figure 1 shows the eigenphase diagram for two doublet scattering states (2A and 2A ) of the CH 3 OH system using HF and CI models.…”

Electron-induced chemistry of alcohols

“…(The time-of-flight spectrometer without a magnetic field of Krishnakumar is better in this respect. 10 ) Our ion lens has two pairs of x, y deflectors, situated near its entrance and its exit, 17 which were used to compensate the deflection by the magnetic field. The electron beam current and, consequently, the sensitivity have been improved in comparison to our earlier work, permitting the detection of weak bands not reported earlier.…”

Communication: Site-selective bond excision of adenine upon electron transfer

“…3 However these methods are not readily scalable for many potential technological or medical applications. Therefore, the achievement of electron-induced site-and bond-specific dissociation (on surfaces using STM tips 4 and in the gas phase using low-energy electron beams [5][6][7][8][9] ) in the mid 2000s was highly significant. The only previous control over dissociation pathways in atom-molecule collisions was demonstrated for potassium impact on gas-phase thymine and uracil.…”