Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution have already been profoundly affected by the application existing ...Read More

Exchange perturbation theory is used to analyze the interaction energy and dipole moment of alkali halide diatomics. It shown that classical ionic models for these systems can be derived by introducing a well-defined set assumptions simplify expressions. Further, it demonstrated extensions include distortion effects formulated give rise effective polarizabilities ions in diatomic. Calculated spectroscopic properties based on model including show improved agreement with experimental data halides.

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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoherence chemistry: controlling chemical reactions [with lasers]Paul Brumer and Moshe ShapiroCite this: Acc. Chem. Res. 1989, 22, 12, 407–413Publication Date (Print):December 1, 1989Publication History Published online1 May 2002Published inissue 1 December 1989https://pubs.acs.org/doi/10.1021/ar00168a001https://doi.org/10.1021/ar00168a001research-articleACS PublicationsRequest reuse permissionsArticle Views773Altmetric-Citations225LEARN ABOUT...

Normal and local mode behavior in molecular systems the transition between them is explored using nonlinear mechanics techniques. Significant insight into this structure of phase space results from a generalized definition normal modes associated identification as (1:1) resonance zeroth order oscillators. In addition to qualitative insight, approach yields simple formula [Eq. (28)] for level excitation at which become possible. Applications H2O overtone spectroscopy dihalomethanes, benzene,...

We review the principles and some recent advances in theory of coherent control molecular processes discuss its experimental realizations. Amongst topics discussed are: bichromatic pump-dump control; interference between N-photons M-photon processes; optical conversion a mixture left- right-handed chiral molecules into an ensemble containing handedness choice; collisional over chaotic dynamics; effects decoherence; solution non-degenerate quantum problem; spontaneous emission other decay processes.

We demonstrate that one can generate and control photocurrents in semiconductors, without bias voltage, through multiple-frequency phase-coherent laser excitation of donors.Received 27 June 1988DOI:https://doi.org/10.1103/PhysRevB.39.3435©1989 American Physical Society

Photoinduced biological processes occur via one-photon absorption in natural light, which is weak, continuous wave, and incoherent, but are often studied the laboratory using pulsed coherent light. Here, we compare response of a molecule to these two very different sources within quantized radiation field picture. The latter shown induce time evolution molecule, whereas former does not. As result, dependence observed experiments will not be relevant process. Emphasis placed on resolving...

A laser-based method of increasing the enantiomeric excess a chiral enantiomer in racemic mixture is described. Neither initial reagents nor incident light need be chiral. Both formal and computational results show that enhancement choice, controlled by laser parameters, can extensive.

Control over the product branching ratio in photodissociation of N${\mathrm{a}}_{2}$ into $\mathrm{Na}(3s)+\mathrm{Na}(3p)$ and $\mathrm{Na}(3s)+\mathrm{Na}(3d)$ is demonstrated using a two-photon incoherent interference control scenario. Ordinary pulsed nanosecond lasers are used at thermal equilibrium heat pipe. Results show depletion $\mathrm{Na}(3d)$ least 25% concomitant increase $\mathrm{Na}(3p)$ yield as relative frequency two scanned.

Initial-value phase-space integral representations for a time-dependent propagator are obtained in the coordinate and momentum representations. To do so we first derive nonuniform semiclassical propagators various representations, obtaining global-time phase indices (Maslov indices) due to caustics. Results include readily implementable general index formulas any type of caustic, including cases where Morse theorem is inapplicable. The method based simply on concatenating uniform short-time...

Recent developments in mathematics and statistical mechanics indicate that efficient intramolecular energy transfer coupled anharmonic oscillator systems can only occur above a critical Ec. A simple method for computing Ec is proposed applied to the Barbanis, Henon–Heiles, Tredgold, Thiele–Wilson systems. The these shown be easily accurately predicted by this technique.

The physical basis for observed long-lived electronic coherence in photosynthetic light-harvesting systems is identified using an analytically soluble model. Three features are found to be responsible their long lifetimes, (i) the small energy gap between excitonic states, (ii) ratio of coupling and (iii) fact that molecular characteristics place system effective low-temperature regime, even at ambient conditions. Using this approach, we obtain decoherence times a dimer model with FMO...

We present a theoretical study of noise-induced quantum coherences in model three-level $V$-type system interacting with incoherent radiation, an important prototype for wide range physical systems ranging from trapped ions to biomolecules and dots. By solving the optical equations motion, we obtain analytic expressions show that they exhibit oscillating behavior limit large excited level spacing $\mathrm{\ensuremath{\Delta}}$...

Light-induced processes that occur in nature, such as photosynthesis and photoisomerization the first steps vision, are often studied laboratory using coherent pulsed laser sources, which induce time-dependent wavepacket molecule dynamics. Nature, however, uses stationary incoherent thermal radiation, sunlight, leading to a totally different molecular response, time-independent steady state. It is vital appreciate this difference order assess role of quantum coherence effects biological...