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Keywords = conical intersections

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6 pages, 2229 KB  
Proceeding Paper
Investigation of Methods for Generating Smooth Continuous Curves Resulting from the Intersection of Conical Surfaces
by Zoya Tsoneva
Eng. Proc. 2025, 104(1), 73; https://doi.org/10.3390/engproc2025104073 - 3 Sep 2025
Viewed by 356
Abstract
Studied extensively in the present paper is a geometric problem related to the intersection of two conical surfaces with crossed axes. The goal was to derive a spatial intersection curve between the surfaces that resembles the classical Viviani curve but is defined as [...] Read more.
Studied extensively in the present paper is a geometric problem related to the intersection of two conical surfaces with crossed axes. The goal was to derive a spatial intersection curve between the surfaces that resembles the classical Viviani curve but is defined as the inter-section of two rotational conical surfaces with crossed axes, forming an asymmetric spatial figure-of-eight shape. These unique spatial curves, as variations of the Viviani curve, possess intriguing geometric properties and are likely to have a wide range of potential applications in the fields of construction and engineering. Their presence can often be linked to the development of complex geometric shapes in architecture, particularly in the design of bridges with unconventional curves in their support structures or situations where inclined support beams intersect with other structural components. They are commonly employed in the construction of tunnels with conical and cylindrical shapes, in addition to various types of vaults and domes. These curves are critical in optimizing structures, such as roofs with intricate geometries or decorative façade elements, and can greatly enhance both their stability and aesthetic appeal. Full article
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22 pages, 4428 KB  
Article
Pore Structure Characteristics and Controlling Factors of the Lower Cambrian Niutitang Formation Shale in Northern Guizhou: A Case Study of Well QX1
by Yuanyan Yin, Niuniu Zou, Daquan Zhang, Yi Chen, Zhilong Ye, Xia Feng and Wei Du
Fractal Fract. 2025, 9(8), 524; https://doi.org/10.3390/fractalfract9080524 - 13 Aug 2025
Viewed by 539
Abstract
Shale pore architecture governs gas storage capacity, permeability, and production potential in reservoirs. Therefore, this study systematically investigates the pore structure features and influencing factors of the Niutitang Formation shale from the QX1 well in northern Guizhou using field emission scanning electron microscopy [...] Read more.
Shale pore architecture governs gas storage capacity, permeability, and production potential in reservoirs. Therefore, this study systematically investigates the pore structure features and influencing factors of the Niutitang Formation shale from the QX1 well in northern Guizhou using field emission scanning electron microscopy (FE-SEM), high-pressure mercury intrusion (HPMI), low-temperature nitrogen adsorption (LTNA), and nuclear magnetic resonance (NMR) experiments. The results show that ① The pore size of the QX1 well’s Niutitang Formation shale is primarily in the nanometer range, with pore types including intragranular pores, intergranular pores, organic matter pores, and microfractures, with the former two types constituting the primary pore network. ② Pore shapes are plate-shaped intersecting conical microfractures or plate-shaped intersecting ink bottles, ellipsoidal, and beaded pores. ③ The pore size distribution showed a multi-peak distribution, predominantly mesopores, followed by micropores, with the fewest macropores. ④ The fractal dimension D1 > D2 indicates that the shale pore system is characterized by a rough surface and some connectivity of the pore network. ⑤ Carbonate mineral abundances are the main controlling factors affecting the pore structure of shales in the study area, and total organic carbon (TOC) content also has some influence, while clay mineral content shows negligible statistical correlation. Full article
(This article belongs to the Special Issue Multiscale Fractal Analysis in Unconventional Reservoirs)
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13 pages, 3937 KB  
Article
Vanillin Quantum–Classical Photodynamics and Photostatic Optical Spectra
by Vladimir Pomogaev and Olga Tchaikovskaya
ChemEngineering 2025, 9(4), 76; https://doi.org/10.3390/chemengineering9040076 - 23 Jul 2025
Viewed by 539
Abstract
Vanillin photoinduced deprotonation was evaluated and analyzed. Vibronic states and transitions were computationally investigated. Optimizations and vertical electron transitions in the gas phase and with the continuum solvation model were computed using the time-dependent density functional theory. Static absorption and emission (photostatic optical) [...] Read more.
Vanillin photoinduced deprotonation was evaluated and analyzed. Vibronic states and transitions were computationally investigated. Optimizations and vertical electron transitions in the gas phase and with the continuum solvation model were computed using the time-dependent density functional theory. Static absorption and emission (photostatic optical) spectra were statistically averaged over the excited instantaneous molecular conformers fluctuating on quantum–classical molecular dynamic trajectories. Photostatic optical spectra were generated using the hybrid quantum–classical molecular dynamics for explicit solvent models. Conical intersection searching and nonadiabatic molecular dynamics simulations defined potential energy surface propagations, intersections, dissipations, and dissociations. The procedure included mixed-reference spin–flip excitations for both procedures and trajectory surface hopping for photodynamics. Insignificant structural deformations vs. hydroxyl bond cleavage followed by deprotonation were demonstrated starting from different initial structural conditions, which included optimized, transition state, and several other important fluctuating configurations in various environments. Vanillin electronic structure changes were illustrated and analyzed at the key points on conical intersection and nonadiabatic molecular dynamics trajectories by investigating molecular orbital symmetry and electron density difference. The hydroxyl group decomposed on transition to a σ-molecular orbital localized on the elongated O–H bond. Full article
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16 pages, 2651 KB  
Article
The Effect of Photoisomerization on the Antioxidant Properties of Sinapic Acid and Methyl Sinapate in Different Solvents: A DFT/TD-DFT Study
by Lei Wang, Chaofan Sun and Lingling Wang
Antioxidants 2025, 14(6), 633; https://doi.org/10.3390/antiox14060633 - 25 May 2025
Cited by 1 | Viewed by 879
Abstract
The impact of photoisomerization on antioxidant properties holds significant implications for fields such as medicine, chemistry, and consumer products. This investigation employs multistate complete active space second-order perturbation theory (MS-CASPT2), complemented by density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, to examine [...] Read more.
The impact of photoisomerization on antioxidant properties holds significant implications for fields such as medicine, chemistry, and consumer products. This investigation employs multistate complete active space second-order perturbation theory (MS-CASPT2), complemented by density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, to examine the photoisomerization behavior of sinapic acid (SA) and methyl sinapate (MS) under ultraviolet (UV) irradiation, while systematically analyzing their antioxidant properties in the S1 state. The computational results, validated by two independent theoretical approaches, confirm that both SA and MS can undergo photoisomerization through conical intersection pathways, providing crucial insights into their non-radiative transition mechanisms. In the S0 state, cis-SA and cis-MS exhibit higher antioxidant activity, while in the S1 state, antioxidant performance is strongly solvent-dependent: trans-SA outperforms in ethyl acetate (Eac) and water, whereas cis-SA is more effective in methanol (MeOH). Notably, the natural population analysis (NPA) charges of all four compounds increase upon photoexcitation, suggesting that photoexcitation enhances antioxidant properties. This study addresses a critical gap in our understanding of the relationship between photoisomerization and antioxidant activity in natural phenolic compounds. Full article
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27 pages, 14431 KB  
Article
Transient-Absorption Pump-Probe Spectra as Information-Rich Observables: Case Study of Fulvene
by Zhaofa Li, Jiawei Peng, Yifei Zhu, Chao Xu, Maxim F. Gelin, Feng Long Gu and Zhenggang Lan
Molecules 2025, 30(7), 1439; https://doi.org/10.3390/molecules30071439 - 24 Mar 2025
Cited by 1 | Viewed by 1471
Abstract
Conical intersections (CIs) are the most efficient channels of photodeactivation and energy transfer, while femtosecond spectroscopy is the main experimental tool delivering information on molecular CI-driven photoinduced processes. In this work, we undertake a comprehensive ab initio investigation of the CI-mediated internal conversion [...] Read more.
Conical intersections (CIs) are the most efficient channels of photodeactivation and energy transfer, while femtosecond spectroscopy is the main experimental tool delivering information on molecular CI-driven photoinduced processes. In this work, we undertake a comprehensive ab initio investigation of the CI-mediated internal conversion in fulvene by simulating evolutions of electronic populations, bond lengths and angles, and time-resolved transient absorption (TA) pump-probe (PP) spectra. TA PP spectra are evaluated on the fly by combining the symmetrical quasiclassical/Meyer–Miller–Stock–Thoss (SQC/MMST) dynamics and the doorway-window representation of spectroscopic signals. We show that the simulated time-resolved TA PP spectra reveal not only the population dynamics but also the key nuclear motions as well as mode–mode couplings. We also demonstrate that TA PP signals are not only experimental observables: They can also be considered as information-rich purely theoretical observables, which deliver more information on the CI-driven dynamics than conventional electronic populations. This information can be extracted by the appropriate theoretical analyses of time-resolved TA PP signals. Full article
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24 pages, 2813 KB  
Article
Axial Ligand Effects on the Mechanism of Ru-CO Bond Photodissociation and Photophysical Properties of Ru(II)-Salen PhotoCORMs/Theranostics: A Density Functional Theory Study
by Niq Catevas and Athanassios Tsipis
Molecules 2025, 30(5), 1147; https://doi.org/10.3390/molecules30051147 - 3 Mar 2025
Cited by 1 | Viewed by 1410
Abstract
Density functional theory (DFT) calculations were employed to study a series of complexes of general formula [Ru(salen)(X)(CO)]0/−1 (X = Cl, F, SCN, DMSO, Phosphabenzene, Phosphole, TPH, CN, N3, NO3 [...] Read more.
Density functional theory (DFT) calculations were employed to study a series of complexes of general formula [Ru(salen)(X)(CO)]0/−1 (X = Cl, F, SCN, DMSO, Phosphabenzene, Phosphole, TPH, CN, N3, NO3, CNH, NHC, P(OH)3, PF3, PH3). The effect of ligands X on the Ru-CO bond was quantified by the trans-philicity, Δσ13C NMR parameter. The potential of Δσ13C to be used as a probe of the CO photodissociation by Ru(II) transition metal complexes is established upon comparing it with other trans-effect parameters. An excellent linear correlation is found between the energy barrier for the Ru-CO photodissociation and the Δσ13C parameter, paving the way for studying photoCORMs with the 13C NMR method. The strongest trans-effect on the Ru-CO bond in the [Ru(salen)(X)(CO)]0/−1 complexes are found when X = CNH, NHC, and P(OH)3, while the weakest for X = Cl, NO3 and DMSO trans-axial ligands. The Ru-CO bonding properties were scrutinized using Natural Bond Orbital (NBO), Natural Energy Decomposition Analysis (NEDA) and Natural Orbital of Chemical Valence (NOCV) methods. The nature of the Ru-CO bond is composite, i.e., electrostatic, covalent and charge transfer. Both donation and backdonation between CO ligand and Ru metal centre equally stabilize the Ru(II) complexes. Ru-CO photodissociation proceeds via a 3MC triplet excited state, exhibiting a conical intersection with the T1 3MLCT excited state. Calculations show that these complexes show bands within visible while they are expected to be red emitters. Therefore, the [Ru(salen)(X)(CO)]0/−1 complexes under study could potentially be used for dual action, photoCORMs and theranostics compounds. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 3rd Edition)
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10 pages, 5266 KB  
Review
Two Quantum Triatomic Hamiltonians: Applications to Non-Adiabatic Effects in NO2 Spectroscopy and in Kr + OH(A2Σ+) Electronic Quenching
by Carlo Petrongolo
Symmetry 2025, 17(3), 346; https://doi.org/10.3390/sym17030346 - 25 Feb 2025
Viewed by 574
Abstract
This review discusses two triatomic Hamiltonians and their applications to some non-adiabatic spectroscopic and collision problems. Carter and Handy in 1984 presented the first Hamiltonian in bond lengths–bond angle coordinates, that is here applied for studying the NO2 spectroscopy: vibronic states, internal [...] Read more.
This review discusses two triatomic Hamiltonians and their applications to some non-adiabatic spectroscopic and collision problems. Carter and Handy in 1984 presented the first Hamiltonian in bond lengths–bond angle coordinates, that is here applied for studying the NO2 spectroscopy: vibronic states, internal dynamics, and interaction with the radiation due to the X˜2A′(A1)−A˜2A′(B2) conical intersection. The second Hamiltonian was reported by Tennyson and Sutcliffe in 1983 in Jacobi coordinates and is here employed in the study of the Kr + OH(A2Σ+) electronic quenching due to conical intersection and Renner–Teller interactions among the 12A′, 22A′, and 12A″ electronic species. Within the non-relativistic approximation and the expansion method in diabatic electronic representations, the formalism is exact and allows a unified study of various non-adiabatic interactions between electronic states. The rotation, inversion, and nuclear permutation symmetries are considered for defining rovibronic representations, which are symmetry adapted for ABC and AB2 molecules, and the matrix elements of the Hamiltonians are then computed. Full article
(This article belongs to the Topic HAT: Hamiltonian Systems—Applications and Theory)
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15 pages, 10496 KB  
Article
A Numerical Study on the Crashworthiness of Corrugated Conical Tubes with Small Semi-Apical Angles and Their Influence Mechanism
by Yiheng Song, Qinyu Lin, Jinxiang Chen and Tidong Zhao
Biomimetics 2025, 10(1), 29; https://doi.org/10.3390/biomimetics10010029 - 6 Jan 2025
Viewed by 1077
Abstract
To develop a new type of biomimetic single-cell and multi-cell energy-absorbing box (tube) featuring conical tubes at the intersection of cell walls, it is necessary to address the issue of large bottom-space requirements in current conical energy-absorbing tubes with superior crashworthiness due to [...] Read more.
To develop a new type of biomimetic single-cell and multi-cell energy-absorbing box (tube) featuring conical tubes at the intersection of cell walls, it is necessary to address the issue of large bottom-space requirements in current conical energy-absorbing tubes with superior crashworthiness due to their large semi-apical angles. This study proposes adding corrugations to conical tubes with small semi-apical angles and modifying the bottom by replacing the last one or two inclined corrugations with vertical ones. Finite element simulation results show that, compared to conventional conical tubes, adding corrugations reduces the optimal semi-apical angle of conical tubes by 5°, with the optimal range being 5–10°. Furthermore, the modification method of replacing inclined corrugations with vertical ones effectively mitigates the challenges of increasing peak crushing force and large end-peak crushing force as the semi-apical angle increases. This structural optimization lays a foundation for the development of new biomimetic single-cell and multi-cell energy-absorbing boxes (tubes) incorporating conical tubes. Full article
(This article belongs to the Special Issue Biomimetic Energy-Absorbing Materials or Structures)
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12 pages, 996 KB  
Article
Spin–Phonon Relaxation Dynamics from a Conical Intersection of Trapped Rydberg Ions
by Manish Chaudhary, Rejish Nath and Weibin Li
Photonics 2024, 11(12), 1135; https://doi.org/10.3390/photonics11121135 - 2 Dec 2024
Viewed by 1859
Abstract
Non-adiabatic processes near conical intersections are rooted in the stronger coupling between electronic and nuclear degrees of freedom. Using a system of two trapped Rydberg ions, their high polarizability and strong dipolar interactions allow to form a conical intersection, where dynamics takes place [...] Read more.
Non-adiabatic processes near conical intersections are rooted in the stronger coupling between electronic and nuclear degrees of freedom. Using a system of two trapped Rydberg ions, their high polarizability and strong dipolar interactions allow to form a conical intersection, where dynamics takes place on a microsecond time scale. Rydberg lifetimes are typically from a few to tens of microseconds, which could affect the conical dynamics. We study the effect of the finite lifetime of the Rydberg state on the vibronic dynamics around the conical intersection via analyzing the master equation. Through mean field and numerical calculations, damping dynamics are found in both the phonon populations and electronic states depending on the initial states. It is found that oscillatory vibronic dynamics can be seen clearly within the Rydberg lifetime, permitting to observe the conical effect in the trapped Rydberg ion system. Full article
(This article belongs to the Section Quantum Photonics and Technologies)
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17 pages, 3188 KB  
Article
Reversible Photochromic Reactions of Bacteriorhodopsin from Halobacterium salinarum at Femto- and Picosecond Times
by Olga Smitienko, Tatyana Feldman, Ivan Shelaev, Fedor Gostev, Arseniy Aybush, Dmitry Cherepanov, Victor Nadtochenko and Mikhail Ostrovsky
Molecules 2024, 29(20), 4847; https://doi.org/10.3390/molecules29204847 - 13 Oct 2024
Cited by 1 | Viewed by 2249
Abstract
The operation of bacteriorhodopsin (BR) from the archaeon Halobacterium salinarum is based on the photochromic reaction of isomerization of the chromophore group (the retinal protonated Schiff base, RPSB) from the all-trans to the 13-cis form. The ultrafast dynamics of [...] Read more.
The operation of bacteriorhodopsin (BR) from the archaeon Halobacterium salinarum is based on the photochromic reaction of isomerization of the chromophore group (the retinal protonated Schiff base, RPSB) from the all-trans to the 13-cis form. The ultrafast dynamics of the reverse 13-cis → all-trans photoreaction was studied using femtosecond transient absorption spectroscopy in comparison with the forward photoreaction. The forward photoreaction was initiated by photoexcitation of BR by pulse I (540 nm). The reverse photoreaction was initiated by photoexcitation of the product K590 at an early stage of its formation (5 ps) by pulse II (660 nm). The conversion of the excited K590 to the ground state proceeds at times of 0.19, 1.1, and 16 ps with the relative contributions of ~20/60/20, respectively. All these decay channels lead to the formation of the initial state of BR as a product with a quantum yield of ~1. This state is preceded by vibrationally excited intermediates, the relaxation of which occurs in the 16 ps time range. Likely, the heterogeneity of the excited state of K590 is determined by the heterogeneity of its chromophore center. The forward photoreaction includes two components—0.52 and 3.5 ps, with the relative contributions of 91/9, respectively. The reverse photoreaction initiated from K590 proceeds more efficiently in the conical intersection (CI) region but on the whole at a lower rate compared to the forward photoreaction, due to significant heterogeneity of the potential energy surface. Full article
(This article belongs to the Section Photochemistry)
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23 pages, 10162 KB  
Article
Targeted Energy Transfer Dynamics and Chemical Reactions
by Natalya Almazova, Serge Aubry and Giorgos P. Tsironis
Entropy 2024, 26(9), 753; https://doi.org/10.3390/e26090753 - 2 Sep 2024
Cited by 1 | Viewed by 1607
Abstract
Ultrafast reaction processes take place when resonant features of nonlinear model systems are taken into account. In the targeted energy or electron transfer dimer model this is accomplished through the implementation of nonlinear oscillators with opposing types of nonlinearities, one attractive while the [...] Read more.
Ultrafast reaction processes take place when resonant features of nonlinear model systems are taken into account. In the targeted energy or electron transfer dimer model this is accomplished through the implementation of nonlinear oscillators with opposing types of nonlinearities, one attractive while the second repulsive. In the present work, we show that this resonant behavior survives if we take into account the vibrational degrees of freedom as well. After giving a summary of the basic formalism of chemical reactions we show that resonant electron transfer can be assisted by vibrations. We find the condition for this efficient transfer and show that in the case of additional interaction with noise, a distinct non-Arrhenius behavior develops that is markedly different from the usual Kramers-like activated transfer. Full article
(This article belongs to the Special Issue New Challenges in Contemporary Statistical Physics)
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12 pages, 3263 KB  
Article
Stationary External Electric Field—Mimicking the Solvent Effect on the Ground-State Tautomerism and Excited-State Proton Transfer in 8-(Benzo[d]thiazol-2-yl)quinolin-7-ol
by Lidia Zaharieva, Ivan Angelov and Liudmil Antonov
Molecules 2024, 29(15), 3506; https://doi.org/10.3390/molecules29153506 - 26 Jul 2024
Cited by 2 | Viewed by 1364
Abstract
The effect of the external electric field on the ground-state tautomerism in 8-(benzo[d]thiazol-2-yl)quinolin-7-ol has been studied by using density functional theory. The compound exists as an enol tautomer (off state) and under the influence of the external electric field a long-range intramolecular proton [...] Read more.
The effect of the external electric field on the ground-state tautomerism in 8-(benzo[d]thiazol-2-yl)quinolin-7-ol has been studied by using density functional theory. The compound exists as an enol tautomer (off state) and under the influence of the external electric field a long-range intramolecular proton transfer can occur, placing the tautomeric proton at the quinolyl nitrogen atom (on state). This is a result of the much higher dipole moment of the end keto tautomer and indicates that the external electric field can be used to mimic the implicit solvent effect in tautomeric systems. In the excited state, the further stabilization of the most polar on state leads to a situation when the excited-state intramolecular proton transfer becomes impossible, limiting the intramolecular rotation to the conical intersection region. Full article
(This article belongs to the Section Physical Chemistry)
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24 pages, 1640 KB  
Article
The Pigment World: Life’s Origins as Photon-Dissipating Pigments
by Karo Michaelian
Life 2024, 14(7), 912; https://doi.org/10.3390/life14070912 - 22 Jul 2024
Cited by 2 | Viewed by 3271
Abstract
Many of the fundamental molecules of life share extraordinary pigment-like optical properties in the long-wavelength UV-C spectral region. These include strong photon absorption and rapid (sub-pico-second) dissipation of the induced electronic excitation energy into heat through peaked conical intersections. These properties have been [...] Read more.
Many of the fundamental molecules of life share extraordinary pigment-like optical properties in the long-wavelength UV-C spectral region. These include strong photon absorption and rapid (sub-pico-second) dissipation of the induced electronic excitation energy into heat through peaked conical intersections. These properties have been attributed to a “natural selection” of molecules resistant to the dangerous UV-C light incident on Earth’s surface during the Archean. In contrast, the “thermodynamic dissipation theory for the origin of life” argues that, far from being detrimental, UV-C light was, in fact, the thermodynamic potential driving the dissipative structuring of life at its origin. The optical properties were thus the thermodynamic “design goals” of microscopic dissipative structuring of organic UV-C pigments, today known as the “fundamental molecules of life”, from common precursors under this light. This “UV-C Pigment World” evolved towards greater solar photon dissipation through more complex dissipative structuring pathways, eventually producing visible pigments to dissipate less energetic, but higher intensity, visible photons up to wavelengths of the “red edge”. The propagation and dispersal of organic pigments, catalyzed by animals, and their coupling with abiotic dissipative processes, such as the water cycle, culminated in the apex photon dissipative structure, today’s biosphere. Full article
(This article belongs to the Special Issue Feature Papers in Origins of Life 2024)
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15 pages, 17807 KB  
Article
The Impact of Pulse Shaping on Coherent Dynamics near a Conical Intersection
by Qici Deng, Junjie Yu, Hongguang Duan and Hongxing He
Photonics 2024, 11(6), 511; https://doi.org/10.3390/photonics11060511 - 27 May 2024
Cited by 1 | Viewed by 1323
Abstract
Utilizing lasers to probe microscopic physical processes is a crucial tool in contemporary physics research, where the influence of laser properties on excitation processes is a focal point for scientists. In this study, we investigated the impact of laser pulses on the quantum [...] Read more.
Utilizing lasers to probe microscopic physical processes is a crucial tool in contemporary physics research, where the influence of laser properties on excitation processes is a focal point for scientists. In this study, we investigated the impact of laser pulses on the quantum yield of electronic wave packets near conical intersections (CIs). To do so, we employed the time non-local quantum master equation to calculate the time-evolution dynamics of wave packets on excited-state potential energy surfaces (PESs) and projected them onto effective reaction coordinates. The waveform of laser pulses was manipulated by varying the relative amplitude, pulse duration, and center wavelengths of Gaussian profiles. Our calculations revealed that the shape of laser pulses has a discernible impact on the dynamic evolution of electrons in excited states. Furthermore, our research indicated that different pulse profiles exhibit a maximum variation of 6.88% in the quantum yields of electronic wave packets near CIs. Our calculations demonstrate the influence of laser pulse waveform on excitation processes, providing a feasible method for exploring the coherent control of wave packets at conical intersections characterized by strong nonadiabatic coupling. Full article
(This article belongs to the Special Issue Ultrafast Optics and Applications)
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19 pages, 9682 KB  
Article
Design of Conical Foundations with Increased Bearing Capacity in Areas of Undermined Soils
by Askar Zhussupbekov, Assel Sarsembayeva, Baurzhan Bazarov and Abdulla Omarov
Appl. Sci. 2024, 14(5), 1816; https://doi.org/10.3390/app14051816 - 22 Feb 2024
Cited by 3 | Viewed by 1819
Abstract
This article discusses the foundations of a conical shape directed with their apex downwards to increase the cross-sectional area and, accordingly, the bearing capacity during settlement and under the influence of horizontal tensile strains in undermined areas. To simulate the deformability of undermined [...] Read more.
This article discusses the foundations of a conical shape directed with their apex downwards to increase the cross-sectional area and, accordingly, the bearing capacity during settlement and under the influence of horizontal tensile strains in undermined areas. To simulate the deformability of undermined and seismically exposed foundations, a three-dimensional expandable box was manufactured and assembled. Models of a conical foundation with an aperture angle of the cones at 90° and 80° were buried into the soil at 0.75 of its height, in order to provide a safety margin for further loading due to an increase in the bearing area when the cone is immersed deeper into the ground. Laboratory and field tests were performed on the vertical loading of single cones before and after horizontal soil displacement. Numerical modeling of the interaction between soil and foundation was carried out for conical foundation models that were considered for laboratory and field testing using the Plaxis 2D (Version 8.2) program. To compare the bearing capacity, isolated shallow foundations with a diameter equal to the cross section of the conical foundation at the intersection with the ground surface were tested. The isolated shallow foundations lost their bearing capacity after 0.15 kN in laboratory tests and after 75 kN in the field tests, while the ultimate bearing capacity of conical foundations with the similar cross section at the soil surface was not achieved, even after 0.2 kN during laboratory tests with horizontal soil displacement and at a load of 100 kN in field tests. Full article
(This article belongs to the Section Civil Engineering)
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