Reliability and performances of real-time time-dependent auxiliary density functional theory

Abstract

We recently adapted the Auxiliary DFT framework as implemented in deMon2k to the simulation of time-dependent problems via the Runge and Gross equations. Our implementation of the so-called Real-Time-Time-Dependent ADFT (RT-TD-ADFT) fully benefits from the algorithms available in deMon2k to carry out variational density fitting, notably the MINRES algorithm recently proposed for self-consistent-field calculations. We test here MINRES for the first time in the context of RT-TD-ADFT.We report extensive benchmarks calculations to assess the reliability of the ADFT framework. These encompass the construction of absorption spectra in the gas phase and in solvent, the calculation of electronic stopping power curves, the irradiation of zeolites by swift ions and the investigation of charge migrations with attosecond time resolution. All our results are very encouraging. We show that even small auxiliary basis sets are sufficient to obtain results almost undisguisable from those obtained with large and flexible auxiliary bases. Overall, we establish the reliability of RT-TD-ADFT to simulate electronics dynamics in large or very large molecular systems.

Following the density evolution using real time density functional theory and density based indexes: Application to model push–pull molecules

“…This approximation becomes particularly beneficial in the case of RT simulations where a different KS density is formed at every propagation step, thus allowing to reduce the computational cost of the simulations without altering the stability and accuracy of the propagation. 11,50 In the present work the…”

“…In the ADFT framework, this fitted density is also adopted to compute and approximate exchange and correlation potential energy. This approximation becomes particularly beneficial in the case of RT simulations where a different KS density is formed at every propagation step, thus allowing to reduce the computational cost of the simulations without altering the stability and accuracy of the propagation 11,50 . In the present work the automatically generated auxiliary basis set GEN‐A2* 51 was adopted for both LR calculations and RT simulations, together with the basis set 6–31+ G(d).…”

Irradiation of Plutonium Tributyl Phosphate Complexes by Ionizing Alpha Particles: A Computational Study

“…In addition, because of the simpler mathematical expression of ρ̃ compared to ρ, the numerical integration of the XC contribution is greatly simplified with ADFT . These features, combined with efficient integral calculation algorithms make ADFT a very appealing framework to conduct RT-TD-DFT simulations, and we previously demonstrated the accuracy of RT-TD-ADFT for a variety of strong perturbation-induced-phenomena, including ion–molecules collisions, or the calculation of stopping power, an observable directly related to the energy deposition process . To conclude, note that the resolution-of-the-identity, which is another means to speed up Coulomb potential evaluation, differs from the ADFT methodology as discussed for example in refs and .…”

“…RT-TD-DFT has also found promising applications to the calculation of electronic stopping power of fast ions in matter. − We finally note the work of Dinh et al to calculate the resonance energy of a secondary electron bound state capture . Recently we have extended RT-TD-DFT to the Auxiliary DFT (ADFT) framework opening up the possibility to deal routinely with large molecular systems . In ADFT, variationally fitted electronic densities are used to decrease the total number of terms in the repulsive Coulomb potential and simplify the numerical integration of the exchange-correlation contribution to the potential.…”

Ab Initio Prediction of a Negative Barkas Coefficient for Slow Protons and Antiprotons in LiF

“…] 20 ] using real-time TDDFT (RT TDDFT), proved the existence of a threshold for proton in LiF. Following this original work that demonstrated the predictive power of ab initio calculations, a wealth of new TDDFT studies on other materials bloomed [21][22][23][24][25][26][27][28][29].…”