The vibrational dynamics of the first four antisymmetric stretch vibrational levels of azide in an ionic glass have been measured and correlated using a heterodyned fifth-order two-dimensional infrared pulse sequence. By rephasing a two-quantum coherence, a process not possible with third-order spectroscopy, solvent effects on the frequencies and anharmonicities of the potential energy surface are measured. Fifth-order pulse sequences are another step towards precisely controlling vibrational coherence in analogy to the manipulation of spins in NMR but with ultrafast time resolution.
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http://dx.doi.org/10.1103/PhysRevLett.94.067402 | DOI Listing |
Sci Rep
January 2025
Yunnan Phosphating Group Co., Ltd, Kunming, 650600, China.
Due to the fluidity of the loose medium inside the waste dump slope, the traditional monitoring system cannot fully reflect the misalignment and slip between particles inside the medium, and it is also difficult to capture the precursor information of the slip of the loose accumulation body. To reveal the dynamic evolution process of the slope instability of the waste dump slope, the coupling test system of the slope instability of the waste dump slope was used to carry out the study of the acoustic emission characteristics of the slope instability dynamic response of the dump slope under the action of vibration, and to quantitatively analyse the staged characteristics of the acoustic emission parameter evolution of the dump slope under the action of different vibration frequencies and its instability initiation node. The results show that with the increase of vibration frequency, the damage mode of the slope model gradually changes from sliding of small particles to large-scale landslides, and presents the stage process of "vibration compaction → vibration equilibrium → dynamic instability"; Under the action of low-frequency and high-amplitude, the slope model mainly shows that the tiny particles and the basement gravel slip, which is difficult to capture with the naked eye, while under the action of high-frequency and low-amplitude, the slope surface is damaged in a large area, and the overall model is unstable; The dynamic instability of the waste dump slope is accompanied by obvious acoustic emission activities, and the changes of the characteristic parameters of acoustic emission reveal, to a certain extent, the evolution of the internal state of the slope in the process of dynamic instability of the waste dump slope and its stage characteristics; The amplitude and energy efficiency of acoustic emission in the time domain show obvious fractal characteristics in the dynamic instability of the waste dump slope.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany.
We explore the role of molecular vibrations in the chirality-induced spin selectivity (CISS) effect in the context of charge transport through a molecular nanojunction. We employ a mixed quantum-classical approach that combines Ehrenfest dynamics for molecular vibrations with the hierarchical equations of motion method for the electronic degrees of freedom. This approach treats the molecular vibrations in a nonequilibrium manner, which is crucial for the dynamics of molecular nanojunctions.
View Article and Find Full Text PDFIUCrJ
January 2025
Dynamic Molecular Materials Laboratory, Department of Life Sciences, University of Modena and Reggio Emilia, Modena, 41125, Italy.
Understanding dynamic processes in molecular crystals is becoming crucial for the development of next-generation smart crystalline materials. In this context, Zwolenik & Makal [(2025). IUCrJ, 12, https://doi.
View Article and Find Full Text PDFData Brief
February 2025
Engineering Institute, Veracruzana University, Juan Pablo II Avenue, Mocambo Campus, Costa Verde, Boca Del Rio City, Veracruz 94292, México.
The data presented here are the result of microtremor measurements at 44 points in three different soil types classified according to their fundamental vibration frequencies, on the metropolitan area of Veracruz-Boca del Río, Mexico. These Data are raw and was obtained using a GÜRALP 6TD model broadband orthogonal triaxial seismometer with an integrated 24-bit digitizer with a minimum recording time of 30 min and a recording rate of 100 samples per second (sps). The microtremor records were used to construct the H/V spectral ratios using the method of Nakamura.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
We revisit the naked transition metal cation (Ti) and methanol reaction and go beyond the standard Landau-Zener (LZ) picture when modeling the intersystem crossing (ISC) rate between the lowest doublet and quartet states. We use both (i) unconstrained Born-Oppenheimer molecular dynamics (BOMD) calculations with an approximate two-state method to estimate population transfer between spin diabats and (ii) constrained dynamics to explore energetically accessible portions of the - 1 crossing seam, where is the total number of internal degrees of freedom. Whereas previous LZ calculations (that necessarily relied on the Condon approximation to be valid) fell short and predicted much slower crossing probabilities than shown in experiment, we show that ISC can occur rapidly because the spin-orbit coupling (SOC) between the doublet and quartet surfaces can vary by 2 orders of magnitude (depending on where in the seam the crossing occurs during dynamics) and the crossing region is revisited multiple times during a dynamics run of a few hundred femtoseconds.
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