Coherent Phonon Dynamics in Plasmonic Gold Tetrahedral Nanoparticle Ensembles.

Coherent phonon modes supported by plasmonic nanoparticles offer prospective applications in chemical and biological sensing. Whereas the characterization of these phonon modes often requires single-particle measurements, synthetic routes to narrow size distributions of nanoparticles permit ensemble investigations. Recently, the synthesis of highly monodisperse gold tetrahedral nanoparticles with tunable edge lengths and corner sharpnesses has been developed.

On the multiphoton ionisation photoelectron spectra of phenol.

The phenol molecule is a prototype for non-adiabatic dynamics and the excited-state photochemistry of biomolecules. In this article, we report a joint theoretical and experimental investigation on the resonance enhanced multiphoton ionisation photoelectron (REMPI) spectra of the two lowest ionisation bands of phenol. The focus is on the theoretical interpretation of the measured spectra using quantum dynamics simulations.

Quantum Interference Paves the Way for Long-Lived Electronic Coherences.

The creation and dynamical fate of a coherent superposition of electronic states generated in a polyatomic molecule by broadband ionization with extreme ultraviolet pulses is studied using the multiconfiguration time-dependent Hartree method together with an ionization continuum model Hamiltonian. The electronic coherence between the hole states usually lasts until the nuclear dynamics leads to decoherence. A key goal of attosecond science is to control the electronic motion and design laser control schemes to retain this coherence for longer timescales.

Controlling the Ultrafast Dynamics of HD by the Carrier-Envelope Phases of an Ultrashort Laser Pulse: A Quasi-Classical Dynamics Study.

A theoretical study on the coupled electron-nuclear dynamics of HD molecular ions under ultrashort, intense laser pulses is performed by employing a well-established quasi-classical model. The influence of the laser carrier-envelope phase on various channel (H + D, D + H, and H + D) probabilities is investigated at different laser field intensities. The carrier-envelope phase is found to govern the dissociation (H + D and D + H) and Coulomb explosion (H + D) channel probabilities.

On Weak-Field (One-Photon) Coherent Control of Photoisomerization.

Photochemistry induced by phase-coherent laser light is an intriguing topic. The possibility of weak-field (one-photon) phase-only control of photoisomerization is controversial. Experimental studies on the weak-field coherent control of cis-trans isomerization have led to conflicting results.

Controlling Chemical Reactions with Laser Pulses.

One of the holy grails of contemporary science is to understand and manipulate chemical reactions to obtain desired products preferentially. To achieve this goal, chemists traditionally choose the correct starting materials and reaction conditions, but it often lacks selectivity and efficiency. A promising alternative is to design laser control schemes and apply them to guide and control chemical reactions.

Controlling Electron Dynamics with Carrier-Envelope Phases of a Laser Pulse.

A theoretical study on the ionization dynamics of carbon atom irradiated with a few-cycle, intense laser field is performed within a quasiclassical model to get mechanistic insights into an earlier reported carrier-envelope phase dependency of ionization probabilities of an atom [ Phys. Rev. Lett.

Non-resonant vibrational excitation of HOD and selective bond breaking.

This paper reports a time-dependent quantum mechanical wave packet study for bond-selective excitation and dissociation of HOD into the H + OD and D + OH channels in the first absorption band. Prior to excitation, the HOD molecule is randomly oriented with respect to a linearly polarized laser field and accurate static dipole moment and polarizability surfaces are included in the interaction potential. Vibrational excitation is obtained with intense, non-resonant 800 nm few-cycle excitation using dynamic Stark effect/impulsive Raman scattering.

Coupled Electron-Nuclear Dynamics on H within Time-Dependent Born-Oppenheimer Approximation.

Quantum dynamical behavior of H in the presence of a linearly polarized, ultrashort, intense, infrared laser pulse has been studied by numerically solving the time-dependent Schrödinger equation with nuclear motion restricted in one-dimension along the direction of laser polarization and electronic motion in three-dimensions. On the basis of the time-dependent Born-Oppenheimer approximation, we have constructed time-dependent potentials for the ground electronic state (1sσ) of H. Subsequent nuclear dynamics is then carried out on these field-dressed potential energy surfaces, and the dissociation dynamics is investigated.

Effect of Vibrational Pre-Excitation on the Dissociation Dynamics of HOD(2+).

Preferential breaking of chemical bonds using few-cycle, intense laser pulse to obtain desired products offer a formidable challenge in understanding ultrafast chemical reactivity. In a recent study [J. Chem.