First-principles interpretation of electron transport though single-molecule junctions using molecular dynamics of electron attached states

The electron transport through the single-molecule junction of 1,4-Diaminobenzene (BDA) is modeled using ab initio quantum-classical molecular dynamics of electron attached states. Observations on the nature of the process are made by time-resolved analysis of energy differences, non-adiabatic transition probabilities and the spatial distribution of the excess electron. The role of molecular vibrations that facilitate the transport by being responsible for the periodic behaviour of these quantities is shown using normal mode analysis. The results support a mechanism involving the electron\u27s direct hopping between the electrodes, without its presence on the molecule, with the prime importance of the bending vibrations that periodically alter the molecule{electrode interactions. No relevant differences are found between results provided by the ADC(2) and SOS-ADC(2) excited state models. Our approach provides an alternative insight into the role of nuclear motions in the electron transport process, one which is more expressive from the chemical perspective

Interpretation of Molecular Electron Transport in Ab Initio Many-Electron Framework Incorporating Zero-point Nuclear Motion Effects

A computational methodology, founded on chemical concepts, is presented for interpreting the role of nuclear motion in the electron transport through Single-Molecule Junctions (SMJ) using many-electron ab initio quantum chemical calculations. Within this approach the electron attached states, modeling the system formed upon the arrival of an electron from the bulk, are computed at the SOS-ADC(2) level along the individual normal modes of the encapsulated molecules. The inspection of the changes in the partial charge distribution of the many-electron states allows the quantification of the electron transport and the estimation of transmission probabilities. This analysis improves the understanding of the relationship between internal motions and electron transport. Two SMJ model systems are studied for validation purposes, constructed from a conductor (BDA, benzene-1,4-diamine) and an insulator molecule (DABCO, 1,4-diazabicyclo[2.2.2]octane). The trends of the resulting transmission probabilities are in agreement with the experimental results, demonstrating the capability of the approach to distinguish between conductor and insulator type systems, thereby offering a straightforward and cost-effective tool for such classifications via quantum chemical calculations

Accurate prediction of vertical ionization potentials and electron affinities from spin-component scaled CC2 and ADC(2) models

The CC2 and ADC(2) wave function models and their spin-component scaled modifications are adopted for predicting vertical ionization potentials (VIPs) and electron affinities (VEAs). The ionic solutions are obtained as electronic excitations in the continuum orbital formalism, making possible the use of existing, widespread quantum chemistry codes with minimal modifications, in full consistency with the treatment of charge transfer excitations. The performance of different variants is evaluated via benchmark calculations on various sets from previous works, containing small and medium-sized systems, including the nucleobases. It is shown that with the spin-scaled approximate methods, in particular the scaled opposite-spin variant of the ADC(2) method the accuracy of EOM-CCSD is achievable at a fraction of the computational cost, also outperforming many common electron propagator approaches

Accurate Prediction of Vertical Ionization Potentials and Electron Affinities from Spin-Component Scaled CC2 and ADC(2) Models

The CC2 and ADC(2) wave function models and their spin-component scaled modifications are adopted for predicting vertical ionization potentials (VIPs) and electron affinities (VEAs). The ionic solutions are obtained as electronic excitations in the continuum orbital formalism, making possible the use of existing, widespread quantum chemistry codes with minimal modifications, in full consistency with the treatment of charge transfer excitations. The performance of different variants is evaluated via benchmark calculations on various sets from previous works, containing small- and medium-sized systems, including the nucleobases. It is shown that with the spin-scaled approximate methods, in particular the scaled opposite-spin variant of the ADC(2) method, the accuracy of EOM-CCSD is achievable at a fraction of the computational cost, also outperforming many common electron propagator approaches

This time it’s different? Effects of the Eurovision Debate on young citizens’ and its consequence for EU democracy – evidence from a quasi-experiment in 24 countries

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.For the very first time in EU history, the 2014 EP elections provided citizens with the opportunity to influence the nomination of the Commission President by casting a vote for the main Europarties’ ‘lead candidates’. By subjecting the position of the Commission President to an open political contest, many experts have formulated the expectation that heightened political competition would strengthen the weak electoral connection between EU citizens and EU legislators, which some consider a root cause for the EU’s lack of public support. In particular, this contest was on display in the so-called ‘Eurovision Debate’, a televised debate between the main contenders for the Commission President broadcasted live across Europe. Drawing on a quasi-experimental study conducted in 24 EU countries, we find that debate exposure led to increased cognitive and political involvement and EU support among young citizens. Unfortunately, the debate has only reached a very small audience