scholarly journals A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation

2021 ◽  
Vol 154 (9) ◽  
pp. 094111
Author(s):  
Aleksander P. Woźniak ◽  
Michał Lesiuk ◽  
Michał Przybytek ◽  
Dmitry K. Efimov ◽  
Jakub S. Prauzner-Bechcicki ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
Laser Field ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Basis Sets ◽  
Field Ionization ◽  
Gaussian Basis Sets ◽  
Systematic Construction

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 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 Ultrafast Dynamics of High-Harmonic Generation in Terms of Complex Floquet Spectral Analysis

Symmetry ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 313 ◽  
Author(s):  
Hidemasa Yamane ◽  
Satoshi Tanaka
Keyword(s):  
Spectral Analysis ◽  
Harmonic Generation ◽  
Laser Field ◽  
Quantum Interference ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Spectral Features ◽  
Quantum Process ◽  
Time Regime ◽  
Long Time

We studied the high-harmonic generation (HHG) of a two-level-system (TLS) driven by an intense monochromatic phase-locked laser based on complex spectral analysis with the Floquet method. In contrast with phenomenological approaches, this analysis deals with the whole process as a coherent quantum process based on microscopic dynamics. We have obtained the time-frequency resolved spectrum of spontaneous HHG single-photon emission from an excited TLS driven by a laser field. Characteristic spectral features of the HHG, such as the plateau and cutoff, are reproduced by the present model. Because the emitted high-harmonic photon is represented as a superposition of different frequencies, the Fano profile appears in the long-time spectrum as a result of the quantum interference of the emitted photon. We reveal that the condition of the quantum interference depends on the initial phase of the driving laser field. We have also clarified that the change in spectral features from the short-time regime to the long-time regime is attributed to the interference between the interference from the Floquet resonance states and the dressed radiation field.

Highly Efficient High-Harmonic Generation in an Orthogonally Polarized Two-Color Laser Field

2005 ◽  
Vol 94 (24) ◽  
Author(s):  
I Jong Kim ◽  
Chul Min Kim ◽  
Hyung Taek Kim ◽  
Gae Hwang Lee ◽  
Yong Soo Lee ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
Laser Field ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Highly Efficient

Enhancing high harmonic generation by the global optimization of a two-color chirped laser field

2019 ◽  
Vol 21 (18) ◽  
pp. 9302-9309 ◽  
Author(s):  
Mohammad Mofared ◽  
Elnaz Irani ◽  
Rasoul Sadighi-Bonabi
Keyword(s):  
Global Optimization ◽  
Harmonic Generation ◽  
Laser Field ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
High Harmonics ◽  
Supercontinuum Spectrum

Enhanced high harmonics are generated by local and global optimization approaches to achieve a supercontinuum spectrum.

scholarly journals Robust enhancement of high harmonic generation via attosecond control of ionization

2019 ◽  
Vol 205 ◽  
pp. 02008
Author(s):  
Barry D. Bruner ◽  
Talya Arusi-Parpar ◽  
Michael Krüger ◽  
Oren Pedatzur ◽  
Gal Orenstein ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
Laser Field ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Ionization Rate ◽  
Generation Efficiency

We demonstrate up to two orders of magnitude enhancements in high harmonic generation efficiency via sub-cycle control and scaling of the ionization rate in a two colour laser field.

High-harmonic generation in an intense femtosecond laser field

2000 ◽  
Author(s):  
ChangHee Nam ◽  
H. J. Shin ◽  
DongGun Lee ◽  
Yong H. Cha ◽  
KyungHan Hong
Keyword(s):  
Femtosecond Laser ◽  
Harmonic Generation ◽  
Laser Field ◽  
High Harmonic ◽  
High Harmonic Generation
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