Quantum Interference Paves the Way for Long-Lived Electronic Coherences

The creation and dynamical fate of a coherent superposition of electronic states generated in a polyatomic molecule by broadband ionization with extreme ultraviolet pulses is studied using the multiconfiguration time-dependent Hartree method together with an ionization continuum model Hamiltonian. The electronic coherence between the hole states usually lasts until the nuclear dynamics leads to decoherence. A key goal of attosecond science is to control the electronic motion and design laser control schemes to retain this coherence for longer timescales. Here, we investigate this possibility using time-delayed pulses and show how this opens up the prospect of coherent control of charge migration phenomenon

Quantum dynamics on

Time-dependent quantum mechanical wave packet calculations have been carried out to study the effect of orientation and rotation of the hydrogen molecule on the reaction S (1D) + H2(X1 Σg+)(v = 0, j = 0–3) → SH(X2Π) + H(2S) using the double many-body expansion (DMBE)/complete basis set (CBS) potential energy surface (PES) by Song and Varandas [J. Chem. Phys. 130, 134317 (2009)]. Reaction probability and integral cross section values were calculated over a range of collision energy values. The cross section values are compared with the experimental values as well as with the other quantum mechanical results. Our calculation shows that reaction probability values strongly depend on the orientation and rotation of the hydrogen molecule. It was also found that rotational excitation of H2 molecule significantly enhances integral reaction cross section values contrary to earlier reported quasi-classical trajectory calculation results

Scanpath Complexity: Modeling Reading Effort Using Gaze Information

Measuring reading effort is useful for practical purposes such as designing learning material and personalizing text comprehension environment. We propose a quantification of reading effort by measuring the complexity of eye-movement patterns of readers. We call the measure Scanpath Complexity. Scanpath complexity is modeled as a function of various properties of gaze fixations and saccades- the basic parameters of eye movement behavior. We demonstrate the effectiveness of our scanpath complexity measure by showing that its correlation with different measures of lexical and syntactic complexity as well as standard readability metrics is better than popular baseline measures based on fixation alone

On the multiphoton ionisation photoelectron spectra of phenol

The phenol molecule is a prototype for non-adiabatic dynamics and the excited-state photochemistry of biomolecules. In this article, we report a joint theoretical and experimental investigation on the resonance enhanced multiphoton ionisation photoelectron (REMPI) spectra of the two lowest ionisation bands of phenol. The focus is on the theoretical interpretation of the measured spectra using quantum dynamics simulations. These were performed by numerically solving the time-dependent Schrödinger equation using the multi-layer variant of the multiconfiguration time-dependent Hartree algorithm together with a vibronic coupling Hamiltonian model. The ionising laser pulse is modelled explicitly within the ionisation continuum model to simulate experimental femtosecond 1+1 REMPI photoelectron spectra. These measured spectra are sensitive to very short lived electronically excited states, providing a rigorous benchmark for our theoretical methods. The match between experiment and theory allows for an interpretation of the features of the spectra at different wavelengths and shows that there are features due to both ‘direct' and ‘indirect' ionisation, resulting from non-resonant and resonant excitation by the pump pulse