Programme

P.75 -- Posters, VCTP-50

Date: Thursday, 7 August 2025

Time: 08:30 - 10:00

TRACKING NUCLEAR VIBRATION USING MASS SPECTROMETRY

Trong-Thanh D. Nguyen (1), Doan-An Trieu (2), Ngoc-Loan Phan (1)

(1) Computational Physics Key Laboratory K002, Department of Physics, Ho Chi Minh City University of Education, Ho Chi Minh City 72711, Vietnam (2) Institute of Fundamental and Applied Sciences, Duy Tan University, Ho Chi Minh City 700000, Vietnam

Tracking ultrafast molecular motion is a fundamental prerequisite for gaining control over quantum processes. One effective way for tracking ultrafast molecular motion is the pump–probe technique, in which an initial pump pulse excites nuclear dynamics, followed by a delayed probe pulse that triggers the fragmentation of molecule – which is known as Coulomb Explosion (CE) [1]. By using mass spectrometry, the ionic signals from the molecule are analyzed to obtain the distribution of fragments versus their kinetic energy, or shortly the Kinetic Energy Release (KER) spectra, which encode nuclear dynamics at the instant CE occurs [1,2]. In this study, we theoretically study the posibility of tracking nuclear vibrations of the ion H₂⁺; in which, the KER spectrum is considered to be contributed mostly by fragments from molecule in two lowest electronic states. By analyzing KER spectra as a function of the time delay between pump and probe pulses, the frequencies of nuclear vibration are extracted via Fourier transform [3]. The results are consistent with previous studies and demonstrate the potential of Coulomb Explosion as an effective tool for probing ultrafast nuclear dynamics [4]. The project is ongoing, aiming to track the nuclear dynamics of more complex molecular systems or those driven by multiple input laser pulses. Keywords: Mass Spectrometry, Coulomb Explosion, Kinetic Energy Release. References: [1] H. Stapelfeldt, E. Constant, and P. Corkum, “Wave packet structure and dynamics measured by Coulomb Explosion”, Physical Review Letters 74, 3780 (1995). [2] H. V. S. Lam, A. S. Venkatachalam, S. Bhattacharyya, K. Chen, K. Borne, E. Wang, R. Boll, T. Jahnke, V. Kumarappan, and A. Rudenko, “Differentiating three-dimensional molecular structures using laser-induced Coulomb explosion imaging”, Physical Review Letters 132, 123201 (2024). [3] M. Magrakvelidze, A. Kramer, K. Bartschat, and U. Thumm, “Complementary imaging of the nuclear dynamics in laser-excited diatomic molecular ions in the time and frequency domains”, Journal of Physics B 47, 124003 (2014). [4] L. Yue and L. B. Madsen, “Dissociation and dissociative ionization of H2+ using the time-dependent surface flux method”, Physical Review A 88, 063420 (2013)

Presenter: Nguyen Dang Trong Thanh