Probing the molecular frame of uracil and thymine with high-harmonic generation spectroscopy

2021 ◽  
Author(s):  
Eleonora Luppi ◽  
Emanuele Coccia
Keyword(s):  
Real Time ◽  
Harmonic Generation ◽  
Configuration Interaction ◽  
High Harmonic ◽  
Three Dimensional ◽  
High Harmonic Generation ◽  
Molecular Plane ◽  
Time Formulation ◽  
Molecular Frame

We present here HHG spectra of uracil and thymine, computed by a real-time formulation of configuration interaction with single excitations. Spectra are obtained as three-dimensional and molecular-plane averages, and as single-polarisation responses.

scholarly journals Role of Exchange and Correlation in High-Harmonic Generation Spectra of H2, N2 and CO2: Real-Time Time-Dependent Electronic-Structure Approaches

2020 ◽  
Author(s):  
Emanuele Coccia ◽  
Eleonora Luppi ◽  
Carlo Federico Pauletti
Keyword(s):  
Real Time ◽  
Harmonic Generation ◽  
Density Functional ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Time Dependent ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Hartree Fock ◽  
Exchange And Correlation

<p>This study arises from the attempt to answer the following question: how different descriptions of electronic exchange and correlation affect the high-harmonic generation (HHG) spectroscopy of H2, N2 and CO2 molecules? We compare HHG spectra for H2, N2 and CO2 with different ab initio electronic structures methods: real-time time-dependent configuration interaction (RT-TDCIS) and real-time time-dependent density functional theory (RT-TDDFT) using truncated basis sets composed of correlated wave functions expanded on Gaussian basis sets. In the framework of RT-TDDFT, we employ PBE and LC-ωPBE functionals. We study HHG spectroscopy by disentangling the effect of electronic exchange and correlation. We first analyse the electronic exchange alone and in the case of RT-TDDFT with LC-ωPBE, we use ω = 0.3 and ω = 0.4 to tune the percentage of long-range Hartree-Fock exchange and of short-range exchange PBE. Then, we added the correlation as described by PBE functional. All the methods give very similar HHG spectra and they seem not to be particularly sensitive to the different description of exchange and correlation or to the correct asymptotic behaviour of the Coulomb potential. Despite this general trend, some differences are found in the region connecting the cutoff and the background. Here, the harmonics can be resolved with different accuracy depending on the theoretical schemes used. We believe that the investigation of the molecular continuum and its coupling with strong fields merits further theoretical investigations in the next future. </p>

Computation of high-harmonic generation spectra of the hydrogen molecule using time-dependent configuration-interaction

2015 ◽  
Vol 114 (7-8) ◽  
pp. 947-956 ◽  
Author(s):  
Alec F. White ◽  
Chiara Josephine Heide ◽  
Peter Saalfrank ◽  
Martin Head-Gordon ◽  
Eleonora Luppi
Keyword(s):  
Harmonic Generation ◽  
Configuration Interaction ◽  
Hydrogen Molecule ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Time Dependent

scholarly journals Role of Exchange and Correlation in High-Harmonic Generation Spectra of H2, N2 and CO2: Real-Time Time-Dependent Electronic-Structure Approaches

2020 ◽  
Author(s):  
Emanuele Coccia ◽  
Eleonora Luppi ◽  
Carlo Federico Pauletti
Keyword(s):  
Real Time ◽  
Harmonic Generation ◽  
Density Functional ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Time Dependent ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Hartree Fock ◽  
Exchange And Correlation

<p>This study arises from the attempt to answer the following question: how different descriptions of electronic exchange and correlation affect the high-harmonic generation (HHG) spectroscopy of H2, N2 and CO2 molecules? We compare HHG spectra for H2, N2 and CO2 with different ab initio electronic structures methods: real-time time-dependent configuration interaction (RT-TDCIS) and real-time time-dependent density functional theory (RT-TDDFT) using truncated basis sets composed of correlated wave functions expanded on Gaussian basis sets. In the framework of RT-TDDFT, we employ PBE and LC-ωPBE functionals. We study HHG spectroscopy by disentangling the effect of electronic exchange and correlation. We first analyse the electronic exchange alone and in the case of RT-TDDFT with LC-ωPBE, we use ω = 0.3 and ω = 0.4 to tune the percentage of long-range Hartree-Fock exchange and of short-range exchange PBE. Then, we added the correlation as described by PBE functional. All the methods give very similar HHG spectra and they seem not to be particularly sensitive to the different description of exchange and correlation or to the correct asymptotic behaviour of the Coulomb potential. Despite this general trend, some differences are found in the region connecting the cutoff and the background. Here, the harmonics can be resolved with different accuracy depending on the theoretical schemes used. We believe that the investigation of the molecular continuum and its coupling with strong fields merits further theoretical investigations in the next future. </p>

scholarly journals Non-perturbative terahertz high-harmonic generation in the three-dimensional Dirac semimetal Cd3As2

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Sergey Kovalev ◽  
Renato M. A. Dantas ◽  
Semyon Germanskiy ◽  
Jan-Christoph Deinert ◽  
Bertram Green ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
High Harmonic ◽  
Three Dimensional ◽  
High Harmonic Generation ◽  
Dirac Semimetal
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