Nonadiabatic quantum molecular dynamics with hopping. II. Role of nuclear quantum effects in atomic collisions

Fischer, Michael; Handt, J.; Schmidt, R.

doi:10.1103/physreva.90.012526

Cited by 7 publications

(6 citation statements)

References 50 publications

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“…In field-induced FSSH, the PESs are optically coupled by the transition dipole moment μ. The basic states that are then employed in the FSSH algorithm can either be the field-free, adiabatic Born-Oppenheimer surfaces (BO-SH) [39,[43][44][45][46][47][48][49][50] or instantaneous Born-Oppenheimer surfaces that are eigenstates of the electronic Hamiltonian including the electric field at time t (IBO-SH) [51][52][53][54][55][56]. However, it has recently been shown that for photoexcitation and stimulated emission processes in an exactly solvable H 2 + model, these approaches suffer from an unphysically high average number of hops per trajectory, which lead to nonphysical results compared to full quantum simulations [57].…”

Section: Introductionmentioning

confidence: 99%

Choice of the electronic basis for field-induced surface hopping

2020

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A method combining an Ehrenfest-like approach, which minimizes the number of surface hops, with Tully's fewest switches surface hopping is proposed for the description of nonadiabatic molecular dynamics in the presence of an external electromagnetic field. When two states are strongly coupled by the applied light field, an Ehrenfest-like approach is employed, which allows the system to be in a coherent superposition. Tully's fewest switches surface hopping (FSSH) is used for the weak-and no-coupling regimes to improve the asymptotic behavior of the method. The decision of which approach to employ at a given time is made based on a simple analysis of Rabi oscillations in a two-state model. The method is tested for two exactly solvable model systems, i.e., a stimulated emission scenario in a pulsed laser field and a photoexcitation scenario in a cw laser field. Position and momentum densities of the nuclei compare well with exact quantum dynamics simulations and improve on both a pure Ehrenfest and a pure FSSH approach. The method is efficient and easily implemented.

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Section: Introductionmentioning

confidence: 99%

Choice of the electronic basis for field-induced surface hopping

2020

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“…It modifies also the hitherto existing interpretation of scattering, as a "bouncing off" mechanism [3,4,22,28,31], like in collisions between two soccer balls. Instead, "fission" via the prolate-prolate configuration strongly suggests, that the final kinetic energy of the fragments is largely independent on impact energy.…”

Section: Microscopic Resultsmentioning

confidence: 97%

“…For systems as large as we are investigating here, NA-QMD is numerically more efficient than its ab initio QMD approximation [49][50][51]. In extension to previous studies [3,[27][28][29]31] we include a normal mode analysis [52] of the vibrational kinetic energy. This method decomposes the total kinetic vibrational excitation energy E vib into the individual contributions of all 174 eigenmodes of C 60 as function of time t according to…”

Section: Microscopic Resultsmentioning

confidence: 99%

“…in 1993 [1], cluster-cluster collisions became a versatile new field of research (for reviews see [2][3][4][5]) with lasting interest [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In particular, fusion between fullerenes has been studied in great detail, both experimentally and theoretically [1,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. Fusion is a universal phenomenon in collisions between complex particles covering many orders in size and energy from heavy ion collisions in nuclear physics [38] to macroscopic liquid droplets [39,40] or even colliding galaxies [41].…”

Section: Introductionmentioning

confidence: 99%

“…For colliding fullerenes one naturally expects a fusion barrier V B of at least the sp 2 bond breaking energy, or more pertinently the Stone-Wales transformation energy [33,34] of a few eV [45] and, according to (1), a fusion cross section of the order of the geometrical one, πR 2 12 ∼ 150Å 2 [29]. Experimentally, however, the fusion barriers are about one order of magnitude larger (around 80 eV) [29] and the cross sections are even two magnitudes smaller (a feẘ A 2 ) [31].…”

Section: Introductionmentioning

confidence: 99%

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Fusion mechanism in fullerene-fullerene collisions: The deciding role of giant oblate-prolate motion

Handt

Schmidt

2015

EPL

Self Cite

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We provide answers to long-lasting questions in the puzzling behavior of fullerene-fullerene fusion: Why are the fusion barriers so exceptionally high and the fusion cross sections so extremely small? An ab initio nonadiabatic quantum molecular dynamics (NA-QMD) analysis of C60+C60 collisions reveals that the dominant excitation of an exceptionally "giant" oblate-prolate Hg(1) mode plays the key role in answering both questions. From these microscopic calculations, a macroscopic collision model is derived, which reproduces the NA-QMD results. Moreover, it predicts analytically fusion barriers for different fullerene-fullerene combinations in excellent agreement with experiments.

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Surface Hopping Dynamics with DFT Excited States

Barbatti

Crespo‐Otero

2014

Topics in Current Chemistry

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Nonadiabatic dynamics simulation of electronically-excited states has been a research area of fundamental importance, providing support for spectroscopy, explaining photoinduced processes, and predicting new phenomena in a variety of specialties, from basic physical-chemistry, through molecular biology, to materials engineering. The demands in the field, however, are quickly growing, and the development of surface hopping based on density functional theory (SH/DFT) has been a major advance in the field. In this contribution, the surface hopping approach, the methods for computation of excited states based on DFT, the connection between these methodologies, and their diverse implementations are reviewed. The shortcomings of the methods are critically addressed and a number of case studies from diverse fields are surveyed.

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Nonadiabatic quantum molecular dynamics with hopping. II. Role of nuclear quantum effects in atomic collisions

Cited by 7 publications

References 50 publications

Choice of the electronic basis for field-induced surface hopping

Choice of the electronic basis for field-induced surface hopping

Fusion mechanism in fullerene-fullerene collisions: The deciding role of giant oblate-prolate motion

Surface Hopping Dynamics with DFT Excited States

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