Geometry Structure Research Articles

Spectral, optical, thermal, dielectric, micro hardness analysis and computational calculations of a novel crystal, 2-amino-3-methylpyridinium 2, 4-dinitrobenzoate

By adapting slow evaporation technique novel single crystals of 2-Amino-3- Methylpyridinium 2, 4-Dinitrobenzoate (AMPD) were synthesized. The grown crystal was subjected to Single crystal X‒Ray Diffraction technique to explicate the crystal structure. The spectral analyses were carried out to identify the vibrational modes of various functional groups. To explore the optical transparency of the synthesized crystal UV‒Visible study has been performed and its cut-off wavelength was found to be 209 nm. By Kurtz‒Perry powder technique, the assessment of second harmonic generation efficiency of the crystal has been calculated. Using TG/DTA analysis, the thermal behavior of the crystal was studied. The mechanical strength of the crystal was examined by Vicker′s micro hardness test and the work hardening coefficient was 3.59, affirming that the grown crystal belongs to soft material category. Optimized structural geometry, vibrational wavenumbers, frontier molecular orbitals energy, chemical reactivity indices and density of states were also computed using DFT method. Nonlinear optical property of the molecule was explored by the first‒order hyperpolarizability calculation. These experimental and theoretical studies reveal that the molecules can be suitable to use in optoelectronic devices.

(Invited) Resolving Catalytic Mechanism at an Electrode Surface: Thermodynamics & Kinetics of Reaction Steps

Computationally, often the energetics of intermediate reaction steps differentiate the efficiency of heterogeneous catalysts for product evolution. Yet, when compared to experiment, kinetic models are applied. For example, a material’s activity measured by one rate of product evolution is plotted as a function of the calculated formation energies of intermediate chemical forms. A critically important reaction for which this dichotomy between experiment and theory exists is the oxygen evolution reaction (OER) from water. In the laboratory group, we employ time-resolved optical and vibrational spectroscopy to deconstruct OER into its individual reaction steps on an electrode surface. In the presentation, I will describe the experimental methodology and the chosen model system, the n-doped SrTiO3/aqueous interface. I’ll show how these experiments identify both the rates and energetics of the first reaction step, the release of a proton and electron from an absorbed water species, denoted by OH* or O*. A recent success was to isolate a Langmuir isotherm of the intermediate population arising within < 2 ps on the SrTiO3 surface. The intermediate population is of trapped holes measured by emission from the conduction band into unoccupied states in the middle of the semi-conductor bandgap. The isotherm is tuned by the pH of the electrolyte. The pH-dependent formation of these intermediates are connected to their pH-dependent decay at microsecond timescales, presumably related to later reaction steps of OER. I'll also present work on the side of vibrational spectroscopy that looks at how the potential energy surface of a particular trapped hole, the terminal oxyl radical, arises in time through the spectral kinetics of its normal mode. A growing area is to apply the particular experimental methodology to a surface of similar electronic structure but diverse crystal geometries, namely polymorphs of TiO2.

Nonadiabatic Molecular Dynamics Simulations Provide Evidence for Coexistence of Planar and Nonplanar Intramolecular Charge Transfer Structures in Fluorazene.

Fluorazene is a model compound for photoinduced intramolecular charge transfer (ICT) between aromatic moieties. Despite intensive studies, both spectroscopic and theoretical, a complete model of its photophysics is still lacking. Especially controversial is the geometry of its ICT structure, or structures. In order to fill in the gaps in the state of knowledge on this important model system, in the present study I report the results of nonadiabatic molecular dynamics (NAMD) simulations of its photorelaxation process in acetonitrile solution. To afford a direct comparison to spectroscopic data, I use the simulation results as the basis for the calculation of the transient absorption (TA) spectrum. The NAMD simulations provide detailed information on the sequence of events during the excited-state relaxation of the title compound. Following initial photoexcitation into the bright S2 state, the molecule undergoes rapid internal conversion into the S1 state, leading to the locally excited (LE) structure. The LE structure, in turn, undergoes isomerization into a population of ICT structures, with geometries ranging from near-planar to markedly nonplanar. The LE → ICT isomerization reaction is accompanied by the decay of the characteristic excited-state absorption band of the LE structure near 2 eV. The anomalous fluorescence emission band of fluorazene is found to originate mainly from the near-planar ICT structures, in part because they dominate the overall population of ICT structures. Thus, the planar ICT (PICT) model appears to be the most appropriate description of the geometry of the ICT structure of fluorazene.

Hardware-in-the-Loop experiments in model ice for analysis of ice-induced vibrations of offshore structures

The study investigated the use of a Hardware-in-the-Loop (HiL) technique applied in model ice experiments to enable the analysis of offshore structures with low natural frequencies under dynamic ice loading. Traditional approaches were limited by facility capacities and ineffective downscaling of the geometry of the offshore structures. The goal of the present study was to overcome these challenges and to enhance the understanding and explore the applicability of a hybrid testing technique in model ice experiments. To achieve the objective, 204 Hardware-in-the-Loop simulations in model Ice (HiLI) were analyzed. Results showed robust behavior and good performance of the HiLI due to minimal variation in measured delay, normalized root mean square error, and peak tracking error and low magnitudes of such parameters despite alterations in factors such as the choice of the numerical structural model, physical prototype, measurement system, and ice type. Notably, the performance of the HiLI was affected when testing with warm model ice or scaling for harsh ice conditions, attributed to a reduced signal-to-noise ratio and instability of the system, respectively. Experimental identification of the critical delay, along with the application of an analytical stability criterion, revealed that the instability observed, was likely induced by reducing the structural stiffness of the numerical structural model to fulfil the scaling requirements when testing for harsh ice conditions. Additionally, the study showed improved HiLI performance when the physical prototype was in contact with the model ice. This observation was further analyzed and is assumed to be caused by the coupling between the ice and physical prototype, causing a coupled and thus increased eigenfrequency of the physical prototype-ice system.

Integrating local energetics into Maxwell-Calladine constraint counting to design mechanical metamaterials.

The Maxwell-Calladine index theorem plays a central role in our current understanding of the mechanical rigidity of discrete materials. By considering the geometric constraints each material component imposes on a set of underlying degrees of freedom, the theorem relates the emergence of rigidity to constraint counting arguments. However, the Maxwell-Calladine paradigm is significantly limited-its exclusive reliance on the geometric relationships between constraints and degrees of freedom completely neglects the actual energetic costs of deforming individual components. To address this limitation, we derive a generalization of the Maxwell-Calladine index theorem based on susceptibilities that naturally incorporate local energetic properties such as stiffness and prestress. Using this extended framework, we investigate how local energetics modify the classical constraint counting picture to capture the relationship between deformations and external forces. We then combine this formalism with group representation theory to design mechanical metamaterials where differences in symmetry between local energy costs and structural geometry are exploited to control responses to external forces.

Revealing the Properties of Electrically Driven Optical Antennas via Conductive Atomic Force Microscope.

Light emission from ultracompact electrically driven optical antennas (EDOAs) has garnered significant attention due to its terahertz modulation bandwidth. Typically, the EDOAs are fixed and nonadjustable once fabricated, thus hindering the attempts to investigate the influence of structural geometry on light emission properties. Here, we propose and demonstrate that the EDOAs can be constructed by carefully manipulating the gold-coated tips of atomic force microscopy operated in conductive mode into contact with the optical antennas covered by insulating film, where the position of the tunnel junction on the antenna surface can be controlled with high accuracy and flexibility. Taking gold nanorod antennas covered by HfO2 film as an example, we found that the highest light generation efficiency is obtained when the tunnel junction is located at the shoulder edge of the nanorod antenna, where the bonding dipolar surface plasmon mode in the junction is spectrally and spatially coupled with the longitudinal radiation mode of the EDOAs. Besides, position variation of the tunnel junction on the nanorod surface also strongly influences the far-field radiation angular distribution and emission spectrum. Numerical simulations are in good agreement with the experimental results. Our findings offer fundamental insights into the influence of structural parameters on the light emission performance of EDOAs, thus leading to better design of EDOAs with high light generation efficiency and powerful functionality.

Six-Coordinated CoII Single-Molecule Magnets: Synthetic Strategy, Structure and Magnetic Properties.

The pursuit of molecule-based magnetic memory materials contributes significantly to high-density information storage research in the frame of the ongoing information technologies revolution. Remarkable progress has been achieved in both transition metal (TM) and lanthanide based single-molecule magnets (SMMs). Notably, six-coordinated CoII SMMs hold particular research significance owing to the economic and abundant nature of 3d TM ions compared to lanthanide ions, the substantial spin-orbit coupling of CoII ions, the potential for precise control over coordination geometry, and the air-stability of coordination-saturated structures. In this review, we will summarize the progress made in six-coordinated CoII SMMs, organized by their coordination geometry and molecular structure similarity. Valuable insights, principles, and new mechanism gleaned from this research and remaining issues that need to be addressed will also be discussed to guide future optimization.

Quantification of Airway Structures by Persistent Homology.

We propose two types of novel morphological metrics for quantifying the geometry of tubular structures on computed tomography (CT) images. We apply our metrics to identify irregularities in the airway of patients with chronic obstructive pulmonary disease (COPD) and demonstrate that they provide complementary information to the conventional metrics used to assess COPD, such as the tissue density distribution in lung parenchyma and the wall area ratio of the segmented airway. The three-dimensional shape of the airway and its abstraction as a rooted tree with the root at the trachea carina are automatically extracted from a lung CT volume, and the two metrics are computed based on a mathematical tool called persistent homology; treeH0 quantifies the distribution of branch lengths to assess the complexity of the tree-like structure and radialH0 quantifies the irregularities in the luminal radius along the airway. We show our metrics are associated with clinical outcomes.

The spectrum of an operator associated with G 2-instantons with 1-dimensional singularities and Hermitian Yang–Mills connections with isolated singularities

abstract: This is the first step in an attempt at a deformation theory for $G_{2}$-instantons with $1$-dimensional conic singularities. Under a set of model data, the linearization yields a Dirac operator $P$ on a certain bundle over $\mathbb{S}^{5}$, called the \textit{link operator}. As a dimension reduction, the link operator also arises from Hermitian Yang--Mills connections with isolated conic singularities on a Calabi--Yau $3$-fold. Using the quaternion structure in the Sasakian geometry of $\mathbb{S}^{5}$, we describe the set of all eigenvalues of $P$, denoted by $\Spec P$. We show that $\Spec P$ consists of finitely many integers induced by certain sheaf cohomologies on $\mathbb{P}^{2}$, and infinitely many real numbers induced by the spectrum of the rough Laplacian on the pullback endomorphism bundle over $\mathbb{S}^{5}$. The multiplicities and the form of an eigensection can be described fairly explicitly. In particular, there is a relation between the spectrum on $\mathbb{S}^{5}$ to certain sheaf cohomologies on~$\mathbb{P}^{2}$. Moreover, on a Calabi--Yau $3$-fold, the index of the linearized operator for admissible singular Hermitian Yang--Mills connections is also calculated, in terms of these sheaf cohomologies. Using the representation theory of $\SU(3)$ and the subgroup $S[U(1)\times U(2)]$, we show an example in which $\Spec P$ and the multiplicities can be completely determined.

3D-printed gradient scaffolds for osteochondral defects: Current status and perspectives.

Articular osteochondral defects are quite common in clinical practice, and tissue engineering techniques can offer a promising therapeutic option to address this issue.The articular osteochondral unit comprises hyaline cartilage, calcified cartilage zone (CCZ), and subchondral bone.As the interface layer of articular cartilage and bone, the CCZ plays an essentialpart in stress transmission and microenvironmental regulation.Osteochondral scaffolds with the interface structure for defect repair are the future direction of tissue engineering. Three-dimensional (3D) printing has the advantages of speed, precision, and personalized customization, which can satisfy the requirements of irregular geometry, differentiated composition, and multilayered structure of articular osteochondral scaffolds with boundary layer structure. This paper summarizes the anatomy, physiology, pathology, and restoration mechanisms of the articular osteochondral unit, and reviews the necessity for a boundary layer structure in osteochondral tissue engineering scaffolds and the strategy for constructing the scaffolds using 3D printing. In the future, we should not only strengthen the basic research on osteochondral structural units, but also actively explore the application of 3D printing technology in osteochondral tissue engineering. This will enable better functional and structural bionics of the scaffold, which ultimately improve the repair of osteochondral defects caused by various diseases.

Self-oxidized AgCu nano-foam with unique phase structure for ethanol sensors breaking through the trade-off between sensitivity and upper linear limit

Comparing to gas ethanol sensors, electrochemical ethanol sensors are promising owing to the low operating temperature, high sensitivity and good accuracy. Common electrochemical ethanol sensors suffer from a general trade-off relationship between sensitivity and upper limit for linear detection. In this work, facile self-oxidized AgCu nano-foam is obtained by simply dealloying of Mg65Ag12.5Cu12.5Y10 metallic glass ribbon in citric acid, which breaks through the trade-off by showing an ultra-high upper linear limit of 1.5 M and good sensitivity of 109.6 μA mM-1 cm-2. Combined experiment and simulation investigations confirm that the ligaments of the AgCu nano-foam is composed of surfaces with interlacing Ag and Cu2O grains that are driven by surface energy, and cores consist of Ag and Cu grains that result from phase separation. Such phase structures, coupled with the geometry merits, lead to fast oxidation dynamics, abundant electroactive sites, good reversibility and stable microstructure, which results in high upper linear limit and a sensitivity improvement of ∼30 times comparing to Cu nano-foam. This work develops a candidate material for high performance sensing of concentrated ethanol, and verifies a promising strategy to prepare efficient catalysts by multilevel-design of geometry and phase structure.

Programmable Carbon Nanotube Networks: Controlling Optical Properties Through Orientation and Interaction.

The lattice geometry of natural materials and the structural geometry of artificial materials are crucial factors determining their physical properties. Most materials have predetermined geometries that lead to fixed physical characteristics. Here, the demonstration of a carbon nanotube network serves as an example of a system with controllable orientation achieving on-demand optical properties. Such a network allows programming their optical response depending on the orientation of the constituent carbon nanotubes and leads to the switching of its dielectric tensor from isotropic to anisotropic. Furthermore, it also allows for the achievement of wavelength-dispersion for their principal optical axes - a recently discovered phenomenon in van der Waals triclinic crystals. The results originate from two unique carbon nanotubes features: uniaxial anisotropy from the well-defined cylindrical geometry and the intersection interaction among individual carbon nanotubes. The findings demonstrate that shaping the relative orientations of carbon nanotubes or other quasi-one-dimensional materials of cylindrical symmetry within a network paves the way to a universal method for the creation of systems with desired optical properties.

Heterogeneous domain adaptation via incremental discriminative knowledge consistency

Heterogeneous domain adaptation is a challenging problem in transfer learning since samples from the source and target domains reside in different feature spaces with different feature dimensions. The key problem is how to minimize some gaps (e.g., data distribution mismatch) presented in two heterogeneous domains and produce highly discriminative representations for the target domain. In this paper, we attempt to address these challenges with the proposed incremental discriminative knowledge consistency (IDKC) method, which integrates cross-domain mapping, distribution matching, discriminative knowledge preservation, and domain-specific geometry structure consistency into a unified learning model. Specifically, we attempt to learn a domain-specific projection to project original samples into a common subspace in which the marginal distribution is well aligned and the discriminative knowledge consistency is preserved by leveraging the labeled samples from both domains. Moreover, domain-specific structure consistency is enforced to preserve the data manifold from the original space to the common feature space in each domain. Meanwhile, we further apply pseudo labeling to unlabeled target samples based on the feature correlation and retain pseudo labels with high feature correlation coefficients for the next iterative learning. Our pseudo-labeling strategy expands the number of labeled target samples in each category and thus enforces class-discriminative knowledge consistency to produce more discriminative feature representations for the target domain. Extensive experiments on several standard benchmarks for object recognition, cross-language text classification, and digit classification tasks verify the effectiveness of our method.

Origami single-end capacitive sensing for continuous shape estimation of morphing structures

In this work, we propose a novel single-end morphing capacitive sensing method for shape tracking, FxC, by combining Folding origami structures and Capacitive sensing to detect the morphing structural motions using state-of-the-art sensing circuits and deep learning. It was observed through embedding areas of origami structures with conductive materials as single-end capacitive sensing patches, that the sensor signals change coherently with the motion of the structure. Different from other origami capacitors where the origami structures are used in adjusting the thickness of the dielectric layer of double-plate capacitors, FxC uses only a single conductive plate per channel, and the origami structure directly changes the geometry of the conductive plate. We examined the operation principle of morphing single-end capacitors through 3D geometry simulation combined with physics theoretical deduction, which deduced similar behavior as observed in experimentation. Then a software pipeline was developed to use the sensor signals to reconstruct the dynamic structural geometry through data-driven deep neural network regression of geometric primitives extracted from vision tracking. We created multiple folding patterns to validate our approach, based on folding patterns including Accordion, Chevron, Sunray and V-Fold patterns with different layouts of capacitive sensors using paper-based and textile-based materials. Experimentation results show that the geometry primitives predicted from the capacitive signals have a strong correlation with the visual ground truth with R-squared value of up to 95% and tracking error of 6.5 mm for patches. The simulation and machine learning constitute two-way information exchange between the sensing signals and structural geometry. By embedding part of the origami surface with morphing single-end capacitive sensors, FxC presents a unique solution that leverages both the mechanical properties of origami and sensing properties of capacitive sensing.

NiO/vermiculite composites prepared for photocatalytic degradation of methanol-water solution and hydrogen generation

A novel eco-friendly NiO/Vm clay based photocatalysts were synthesized from two vermiculites (Vm1 and Vm2) and nickel(II) nitrate hexahydrate (Ni(NO3)2·6H2O salt precursor by the chemical precipitation without and with the sodium hydroxide (NaOH) or ammonium hydroxide (NH4OH, 28% NH3 in H2O) as precipitation agents (Synthesis A) in comparison with the solid-state thermal decomposition (Synthesis B) at 600 °C. Structural properties of all specimens were characterized by X-ray fluorescence, scanning electron microscopy, X-ray diffraction, infrared (IR) and Raman spectroscopy. The photocatalytic performance of NiO/Vm composites was evaluated under UV radiation (λ = 254 nm) for decomposition of methanol-water to hydrogen over 4-h and the stable yield of hydrogen over the 24-h periods. The NaOH and NH4OH affected the NiO crystallite size and therefore the photocatalytic activity during 4 h. Different 2:1 layer charge of Vm1 (0.82 e−) and Vm2 (0.40 e−) and the specific surface area of Vm1 (about 43 m2/g) and Vm2 (about 34 m2/g) supported H2 yield of 628.2 μmol/gcat. and 596.8 μmol/gcat., close to 657.0 μmol/gcat. produced in the presence of commercial photocatalyst TiO2 Evonik P25. Crystalline NiO precipitated and anchored in NiO/Vm composites contained smaller crystallites than those in free NiO. Vermiculite silica surface supports coverage of NiO by hydrogen bonding to Si-OH groups influencing the geometry of the NiO crystal structure (disorder NiO(X)). The heterojunction with Si-O-Ni bonding, at which electrons transfer from Vm to NiO cause enriching electron density in NiO and favoring its photocatalytic activity. Photocatalytic hydrogen generation from methanol–water mixture at the presence of all specimens indicated the main product H2 and minimum by-products CH4 and CO. The stable hydrogen production for 24 h was confirmed only in the presence NiO/Vm1–24 while maintaining the NiO(X) in small crystallites. The thermal solid-state procedure provided the gradual dehydration of vermiculites and Ni(NO3)2·6H2O to the same amount and crystallinity of NiO in NiO/Vm1 and NiO/Vm2 composites. The results of this work confirm that vermiculites mixed layer structures with different negative layer charge play a dominant role as semiconductors for anchored NiO. The photocatalytic activity of NiO/vermiculite composites can be harnessed to treat wastewater containing organic contaminants.

Investigation of the Zero-Frequency Component of Nonlinear Lamb Waves in a Symmetrical Undulated Plate.

When an ultrasonic pulse propagates in a thin plate, nonlinear Lamb waves with higher harmonics and a zero-frequency component (ZFC) will be generated because of the nonlinearity of materials. The ZFC, also known as the static displacement or static component, has its unique application on the evaluation of early-stage damages in the elastic symmetrical undulated plate. In this study, analysis of the excitation mechanism of the ZFC and the second harmonic component (SHC) was theoretically and numerically investigated, and the material early-stage damage of a symmetrical undulated was characterized by studying the propagation of nonlinear Lamb waves. Both the ZFC and SHC can be effectively employed in monitoring the material damages of the undulated plate in its early stage. However, several factors must be considered for the propagation of the SHC in an undulated plate because of the geometric curvature and interference between the second harmonics during propagation, preventing efficient application of this technique. If the fundamental wave can propagate in the plate regardless of the plate boundary conditions, an accumulative effect always exists for the ZFC in a thin plate, indicating that the ZFC is independent of the structural geometry. This study reveals that the ZFC-based inspection technique is more efficient and powerful in characterizing the damages of a symmetrical undulated plate in the early stage of service compared to the second harmonic method.

CDGT: Constructing diverse graph transformers for emotion recognition from facial videos

Recognizing expressions from dynamic facial videos can find more natural affect states of humans, and it becomes a more challenging task in real-world scenes due to pose variations of face, partial occlusions and subtle dynamic changes of emotion sequences. Existing transformer-based methods often focus on self-attention to model the global relations among spatial features or temporal features, which cannot well focus on important expression-related locality structures from both spatial and temporal features for the in-the-wild expression videos. To this end, we incorporate diverse graph structures into transformers and propose a CDGT method to construct diverse graph transformers for efficient emotion recognition from in-the-wild videos. Specifically, our method contains a spatial dual-graphs transformer and a temporal hyperbolic-graph transformer. The former deploys a dual-graph constrained attention to capture latent emotion-related graph geometry structures among local spatial tokens for efficient feature representation, especially for the video frames with pose variations and partial occlusions. The latter adopts a hyperbolic-graph constrained self-attention that explores important temporal graph structure information under hyperbolic space to model more subtle changes of dynamic emotion. Extensive experimental results on in-the-wild video-based facial expression databases show that our proposed CDGT outperforms other state-of-the-art methods.

From virtual to actual assisted tape placement − application of the Frenet frame to robotic steering trajectories

A novel computational tool is presented that integrates the design and manufacturing of variable-angle tow composites for automated tape placement, facilitating the creation of tow-steered trajectories for cut-outs. Steering movements of the robot are planned and executed within a MATLAB virtual environment via short paths and linear commands. Leveraging piecewise-continuous clothoid splines and the Frenet frame, the tool furnishes crucial details on trajectory vectors, steering angles, and curvatures. Via four integrated modules, the user can define input parameters such as the robot’s actuators and structural geometry, allowing for the subsequent visualisation of the steered trajectories as well as the generation of the manufacturing code. Finally, to assess the potential and limitations of this methodology, the file containing all details is integrated into the Kuka KR L240-2 robot model to continuously steer a carbon fibre/PEEK tape around an elliptical cut-out in a composite panel using laser-assisted tape placement, representative of an access hole in an aircraft wing.

Shape memory polymer lattice structures with programmable thermal recovery time

Shape memory polymer (SMP) lattice structures have garnered considerable attention due to their intrinsic capability for self-recovery and mechanical reconfiguration. The temporal path, encompassing aspects such as recovery time and deployment sequence, of the shape recovery process in SMP lattice structures holds paramount significance across various domains, including but not limited to medical devices and space deployable structures. Nonetheless, the programming of shape recovery time or deployment sequences in SMP lattice structures, particularly in scenarios devoid of external controllers, remains a challenge. In addressing these challenges, this study presents a novel class of SMP structures endowed with customizable thermal recovery times and programmable deployment sequences, leveraging the influence of structural geometry. Notably, the programmable recovery time and serialized deployment behavior of the proposed SMP lattice structure are achieved within a constant temperature environment, obviating the need for external time-varying stimuli. Finite element simulations and experimental validations corroborate that the proposed SMP structures can be programmed to exhibit recovery times spanning from mere seconds to several hundred seconds. Moreover, a three-stage sequential recovery behavior is attained without necessitating prior local configuration programming. Furthermore, exploiting the distinctive sequential reversibility inherent in a constant high-temperature environment, the designed lattice structure showcases the ability to transition to multiple distinct stable configurations by modulating the duration of high-temperature exposure. The proposed recovery time programmable SMP lattice structure thus presents a viable avenue for realizing intricate multistage controllable shape-shifting structures devoid of external control equipment.

The controllable of BODIPY dimers without installing blocking groups as both fluorescence and singlet oxygen generators

AbstractWe compared a range of BODIPY dimer derivatives without installing blocking groups by optimizing geometry structures and analyzing energies, frontier molecular orbitals, Chole&amp;Cele map, electron density difference, spin‐orbit coupling (SOC) matrix and decay rate constants from excited states. The dihedral angles of the β‐β‐linked BODIPY dimer and the α‐α‐linked BODIPY dimer tend to flatten in the T1 state, which is detrimental to the occurrence of the intersystem crossing (ISC). Conversely, the dihedral angle of the meso‐β‐linked BODIPY dimer, the meso‐meso‐linked BODIPY dimer and α‐γ‐linked BODIPY dimer is within the range of 125°–143° in the T1 state, facilitating ISC and the generation of singlet oxygen. Notably, the transition from S1 to S0 involving lowest unoccupied molecular orbital to highest occupied molecular orbital with long‐wavelength emission and moderate oscillator strength underpins the remarkable long emission peaks observed experimentally for α‐γ‐linked BODIPY dimer. Moreover, the apparent SOC matrix enhances the ISC process, resulting in a respectable efficiency in generating singlet oxygen for this dimer. In meso‐β‐linked BODIPY, meso‐meso‐linked BODIPY, and α‐γ‐linked BODIPY, the S1→T1 process is characterized by a significant charge transfer, specifically transitioning from the 1CT state to the 3LE state, indicative of a spin‐orbit charge transfer ISC (SOCT‐ISC) mechanism. The ability to regulate the photosensitivity of BODIPY dimers by adjusting the dihedral angle between the two units in the T1 state unveils new avenues for designing high‐performance photosensitizers for both therapeutic and imaging applications.