Programme

P.95 -- Posters, VCTP-50

Date: Thursday, 7 August 2025

Time: 08:30 - 10:00

Multielectron Effects in the High-Order Harmonic Generation Spectrum of Magnesium

Nhat-Hao Le-Tran (1), Duong D. Hoang-Trong (2,3), Doan-An Trieu (4), Ngoc-Loan Phan (1)

(1) Ho Chi Minh City University of Education, Ho Chi Minh City, Vietnam; (2) Simulation in Materials Science Research Group, Science and Technology Advanced Institute, Van Lang University, Ho Chi Minh City, Vietnam; (3) Faculty of Applied Technology, School of Technology, Van Lang University, Ho Chi Minh City, Vietnam; (4) Institute of Fundamental and Applied Sciences, Duy Tan University, Ho Chi Minh City, Vietnam

Multielectron effects are critical for accurately modeling the interaction between atoms and intense laser pulses. While the single active electron (SAE) approximation considers only the outermost electron to be active, multielectron effects can be understood as the interaction between the active electron and the laser-induced dipole of the remaining electrons in the ion – a phenomenon known as multielectron polarization (MEP). Accordingly, MEP is expected to exhibit significant effects in targets with high polarizability. In this work, we investigate the influence of MEP on the high-order harmonic generation (HHG) spectrum of the magnesium atom, which has a relatively simple electronic structure and a highly polarizable ionic core. By solving the time-dependent Schrödinger equation (TDSE) for the active electron both with and without the MEP, we show that increasing the laser intensity leads to the enhancement of intensity in the near-cutoff region of the HHG spectrum. By analyzing ionization rates and HHG time profiles, we figure out that this enhancement is attributed to the suppression of laser-induced ionization and the increase in the recombination probability. Furthermore, MEP is observed to shift the HHG emission time to earlier moments compared to the case without MEP. These findings underscore the importance of incorporating MEP in strong-field simulations and suggest extending such studies to atoms with highly polarizable cores and under varied laser parameters to fully characterize MEP’s role in HHG.

Presenter: Lê Trần Nhật Hào