The O( 3 P) + C 2 H 4 reaction, of importance in combustion and atmospheric chemistry, stands out as a paradigm reaction involving triplet- singlet-state potential energy surfaces (PESs) interconnected by intersystem crossing (ISC). This poses challenges for theory experiments owing to the ruggedness high dimensionality these potentials, well long lifetimes collision complexes. Primary products from five competing channels (H CH CHO, CO, HCO, O) branching ratios (BRs) are determined crossed...

We solve the time-dependent Schr\"odinger equation for atomic hydrogen in an intense field using spherical coordinates with a radial grid and harmonic basis angular part. present high-order spectra based on three different forms, dipole, dipole velocity, acceleration two gauges, length velocity gauges. The relationships among phases obtained from Fourier transform of forms are discussed detail. Although quantum mechanics is gauge invariant gauges should give identical results, computation...

The reaction of O(3P) with C2H4, importance in combustion and atmospheric chemistry, stands out as paradigm involving not only the indicated triplet state potential energy surface (PES) but also an interleaved singlet PES that is coupled to surface. This poses great challenges for theory experiment, owing ruggedness high dimensionality these potentials, well long lifetimes collision complexes. Crossed molecular beam (CMB) scattering experiments soft electron ionization detection are used...

The conventional understanding of bimolecular reactions, which either proceed directly via well-defined transition states or pass through potential energy wells, is well-established. However, increasing attention and interest have been drawn to nontraditional reaction pathways, such as roaming mechanisms. Here, full-dimensional dynamics simulations on a machine learning-based surface reveal that the Cl + C2H2→C2H+HCl dominated by two mechanisms—Cl-roaming H-roaming—rather than direct...

The diabatic photodissociation and photoionization processes of the NaI molecule are studied theoretically using quantum wave packet method. A pump laser pulse is used to prepare a dissociation that propagates through both ionic channel (NaI→Na++I−) covalent (NaI→Na+I). Stark control dynamics probe employed ionize products from two channels. Based on first order nonresonant nonperturbative dynamic effect, probabilities branching ratio channels can be controlled. Moreover final photoelectron...

Collision-induced and complex-mediated roaming mechanisms are revealed for an important bimolecular reaction in combustion.

The ladder-type population transfer of the HF molecule steered by four-color harmonic laser pulses (HLPs) is investigated using time-dependent quantum wave packet method. It found that although there exist large background excitations and many (resonant) transition pathways during driving, nearly 100% could be transferred to target state. In particular, such a process coherently controlled changing phases four HLPs, especially fundamental second which can accounted for in part combined...

High-level ab initio calculations are performed to examine previously unexplored regions of full-dimensional potential energy surfaces that connect the conventional and recently reported "roaming" saddle points for H2CO CH3CHO unimolecular dissociations form molecular products, H2 + CO CH4 CO, respectively. The aim this investigation is determine whether or not there large barriers separating these their associated intrinsic reaction pathways. results fundamental significance in formulating...

The interference minimum in the high-order harmonic spectrum of H${}_{2}{}^{+}$ is studied by solving full three-dimensional time-dependent Schr\"odinger equation for electronic motion keeping nuclei fixed. two-center model works well when internuclear distance around its equilibrium value where also recombination to ${}^{2}{\ensuremath{\Sigma}}_{\mathrm{g}}^{+}$ (1$s$${\ensuremath{\sigma}}_{\mathrm{g}}$) ground state dominates. As increased, first shifts position compared with prediction...

We present a quasiclassical trajectory study of the photodissociation CH3CHO using global ab initio-based potential energy surface. Calculations are performed at total 160 kcal/mol, corresponding to photolysis wavelength 230 nm, and with all trajectories initiated from acetaldehyde minimum. Many product channels energetically accessible observed this energy, branching ratios these presented. identify minor channel giving H2O plus vinylidene or acetylene. Mechanisms identified for products,...

The dissociation dynamics of Br2 molecules induced by two femtosecond pump pulses are studied based on the calculation time-dependent quantum wave packet. Perpendicular transition from XΣg+1 to AΠ1u+3 and Π1u+1 parallel BΠ0u+3, involving product channels Br (P3∕22)+Br (P3∕22) (P3∕22)+Br* (P1∕22), respectively, taken into account. Two create dissociating packets interfering with each other. By varying laser parameters, interference can be controlled, probabilities three excited states changed...

The field-free orientation induced by a single-cycle terahertz (THz) laser pulse is studied for two “heavy” molecules, NaI and IBr. Two methods are used compared in the calculations: One to solve exact time-dependent Schrödinger equation (ETDSE) considering full-rovibrational degrees of freedom, other invoke rigid-rotor approximation (RRA). Calculations performed central frequency varying from 0.05 1.0 THz peak intensity taken be 5 × 107, 2 108, 108 W/cm2, respectively. degree orientation,...

The orientation and predissociation dynamics of the NaI molecule are studied by using a time-dependent wavepacket method. is first pre-oriented single-cycle pulse (SCP) in terahertz (THz) region then predissociated femtosecond pump pulse. influence molecular field-free on detail. We calculate radial angular distributions, degrees, populations for both ground excited electronic states. It found that pre-orientation affects distributions significantly, it has weak distributions. By varying...

Can a molecule be efficiently activated with large amount of energy in single collision fast atom? If so, this type will greatly affect molecular reactivity and equilibrium systems where abundant hot atoms exist. Conventional expectation transfer (ET) is that the probability decreases exponentially transferred, hence what we label "super transfer" negligible. We show, however, collisions between an atom for which chemical reactions may occur, such as those translationally H ambient acetylene...

We report Trajectory Surface Hopping (TSH) calculations of CH3CHO photodissociation involving three electronic states, S1, T1, and S0, with a focus on the radical products CH3 + HCO, which can be formed from both T1 S0. use previously reported potential energy surfaces spin–orbit couplings for S0 new coupling S1 here. Roughly 32 000 trajectories are performed at energies corresponding to seven photolysis wavelengths between 372 230 nm. Motivated by recent experiments, we examine branching...

Quasi-classical trajectory (QCT) calculations are performed on the molecular products CO + CH4via tight transition state (TS) and global minimum configurations. With aid of this theoretical evidence, we have re-examined experimental results published previously to clarify controversial issue photodissociation dynamics CH3CHO at 248 nm. For (v = 0 1) bimodal rotational distributions obtained [K.-C. Hung, P.-Y. Tsai, H.-K. Li, K.-C. Lin, J. Chem. Phys., 2014, 140, 064313], low-rotational (J)...

We model the process of high-order harmonic generation by solving time-dependent Schrödinger equation for H+2 in fixed nuclei approximation including full 3D electron motion nonvanishing angles between nuclear axis and linear polarization driving pulse. show that coherent laser coupling induced 2Σ+g(1sσg) ground state first excited 2Σ+u(2pσu) leads to two dominating amplitudes may interfere: describing recombination back into σg σu states, respectively. These interfere destructively or...

Translationally hot H collisions with the acetylene are investigated using quasiclassical trajectory calculations, on a recent full-dimensional ab initio-based potential energy surface. Three outcomes focused on: non-reactive transfer via prompt collisions, formation of vinyl complex, and reactive chemical H-atom exchange, also complex formation. The details these presented correlated collision lifetime. Large is found formation, which can subsequently decay back to reactants, event, or new...

The photoassociation processes via the pump-dump scheme for heternuclear (Na + H → NaH) and homonuclear Na Na2) molecular systems are studied, respectively, using time-dependent quantum wavepacket method. For both systems, initial atom pair in continuum of ground electronic state (X(1)Σ(+)) is associated into molecule bound states excited (A(1)Σ(+)) by pump pulse. Then driven a time-delayed dumping pulse, prepared excited-state can be transferred to state. It found that process induce...

The atom-atom-ion three-body recombination (TBR) of mixed 4He and X- (X = H or D) systems is investigated by solving the Schrödinger equation using adiabatic hyperspherical representation method. It shown that dominant products after a TBR in ultracold limit (E ≤ 0.1 mK × kB) are different for two systems. For 4He4HeH- system, rate into 4HeH- ion nearly orders magnitude larger than neutral 4He2 molecule. In contrast, yield little higher 4HeD- 4He4HeD- system. Furthermore, since potentials...

Abstract We adopt the genetic algorithm to fit potential energy curve for B 1 Π state of 85 Rb 133 Cs molecule based on data rovibrational levels, which were observed previously by Fourier-transform spectroscopy and photoassociation spectroscopy. explore effect different hyperparameter settings evolutionary process final results optimise performance algorithm. Finally, fitting procedure can reproduce levels with an error less than 0.06 cm −1 compared experimental data.

An accurate, global, full-dimensional potential energy surface (PES) of NaCl + has been constructed by the fundamental invariant-neural network (FI-NN) fitting based on roughly 13,000 ab initio energies at level CCSD(T)-F12a/aug-cc-pVTZ, with small error 0.16 meV. Extensive quasiclassical trajectory (QCT) calculations were performed this PES to investigate transfer process collision four different energies. Various quantities obtained, including cross-sections, probability, average transfer,...

We present a deperturbation analysis of the spin-orbit-coupled $A{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ and $b{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{\ensuremath{\Pi}}}_{{0}^{+}}$ states LiRb based on rovibrational energy levels observed previously by photoassociation spectroscopy in bosonic $^{7}\mathrm{Li}\phantom{\rule{0.16em}{0ex}}^{85}\mathrm{Rb}$ molecule. Using genetic algorithm (GA), we optimize pointwise ab initio potential curves state...