• Manabendra Sarma

Articles written in Journal of Chemical Sciences

• Selective control of HOD photodissociation using CW lasers

Selective control of HOD photodissociation (H-O + D $\leftarrow$ HOD → H + O-D) has been theoretically investigated using CW lasers with appropriate carrier frequency and |0, 0$\rangle$, |0, 1$\rangle$ and |0, 2$\rangle$ with zero quantum of excitation in the O-H bond and zero, one and two quanta of excitation in the O-D bond as the initial states. Results indicate that the O-H bond in HOD can be selectively dissociated with a maximum flux of 87% in the H + O-D channel from the ground vibrational state |0, 0$\rangle$. For the O-D bond dissociation, it requires two quanta of excitation (|0, 2$\rangle$) in the O-D mode to obtain 83% flux in the H-O + D channel. Use of a two colour laser set-up in conjunction with the field optimized initial state (FOIST) scheme to obtain an optimal linear combination of |0, 0$\rangle$ and |0, 1$\rangle$ vibrational states as the initial state provides an additional 7% improvement to flux in the H-O + D channel as compared to that from the pure |0, 1$\rangle$ state.

• Calculation of vibrational excitation cross-sections in resonant electron-molecule scattering using the time-dependent wave packet (TDWP) approach with application to the ${}^2\Pi$ CO- shape resonance

Results from application of a new implementation of the time-dependent wave packet (TDWP) approach to the calculation of vibrational excitation cross-sections in resonant e-CO scattering are presented to examine its applicability in the treatment of e-molecule resonances. The results show that the SCF level local complex potential (LCP) in conjunction with the TDWP approach can reproduce experimental features quite satisfactorily.

• Vibrational excitation resulting from electron capture in LUMO of F2 and HCl - A treatment using the time-dependent wave packet approach

Vibrational excitation cross-sections $\sigma_{v_f \leftarrow v_i}$(𝐸) in resonant e-F2 and HCl scattering are calculated from transition matrix elements $T_{v_f \leftarrow v_i}$(𝐸) obtained using Fourier transform of the cross correlation function $\langle \phi_{v_f} (R) | \Phi_{v_i} (R, t) \rangle$. where $\Psi_{v_i} (R,t) \approx e^{i \hbar H_{AB^-}(R)t} \phi_{v_i} (R)$. Time evolution under the influence of the resonance anionic Hamiltonian H$_{AB^-}$ (AB=F2/HCl) is effected using Lanczos reduction technique followed by fast Fourier transform and the target (AB) vibrational eigenfunctions $\phi_{ν_i}$ (𝑅) and $\phi_{v_f}$ (𝑅) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curve of the neutral target. The resulting vibrational excitation cross-sections provide reasonable agreement with experimental and other theoretical results.

• Journal of Chemical Sciences

Volume 135, 2023
All articles
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• Editorial Note on Continuous Article Publication

Posted on July 25, 2019