Van Der Waals Effects Research Articles

Adsorption mechanism of cefradine on three microplastics: A combined molecular dynamics simulation and density functional theory calculation study

Microplastics and antibiotics are receiving increasing attention as two emerging pollutants in the aquatic ecosystem. The absorption of antibiotics by microplastics can potentially intensify their impact on marine organisms and human health. However, the detailed mechanisms underlying this interaction remain to be elucidated. Through molecular dynamics (MD) simulations and density functional theory (DFT) calculations, this study investigated the adsorption of cefradine (CED) onto three typical microplastics (MPs)-polyethylene (PE), polypropylene (PP), and polyamide (PA). The results of the molecular dynamics simulations showed that the interaction energy between CED and microplastics followed the order of PA-CED > PP-CED > PE-CED, indicating that PA microplastics had the highest adsorption capacity for CED antibiotics. The total energy contribution of the microplastics-cefradine (MPs-CED) systems suggested that the van der Waals and electrostatic interactions were the two primary mechanisms for the adsorption of CED by these three microplastics. In DFT calculations, the adsorption of CED on PA was found to be significantly influenced by both electrostatic and van der Waals effects, while the main driving force in the adsorption of PE and PP is van der Waals effect. In addition, IGMH analysis and AIM topological analysis confirmed that the adsorption of CED on PA relied heavily on the synergistic effect of hydrogen bonding and the van der Waals effect. The findings of this study validate the results obtained from molecular dynamics simulations, laying a foundation for a comprehensive exploration of the interaction mechanisms between microplastics and organic pollutants by integrating MD simulations and DFT calculations.

Molecularly imprinted beads based on modified cellulose hydrogel:A novel solid phase extraction filler for specific adsorption of camptothecin

Traditional solid phase extraction (SPE) suffers from a lack of specific adsorption. To overcome this problem, a combination of adsorption method and molecular imprinting technology by polydopamine modification was proposed to realize specific recognition of target compounds in SPE, which is of great significance to improve the separation efficiency of SPE. Cellulose hydrogel beads were prepared by dual cross-linking curing method and modified with polydopamine to make them hydrophilic and biocompatible. Subsequently, cellulose hydrogel-based molecularly imprinted beads (MIBs) were synthesized by surface molecular imprinting technology and used as novel column fillers in SPE to achieve efficient adsorption (34.16 mg·g−1) with specific selectivity towards camptothecin (CPT) in 120 min. The simulation and NMR analysis revealed that recognition mechanism of MIBs involved hydrogen bond interactions and Van der Waals effect. The MIBs were successful used in separating CPT from Camptotheca acuminata fruits, exhibiting impressive adsorption capacity (1.19 mg·g−1) and efficient recovery of CPT (81.54 %). Thus, an environmentally friendly column filler for SPE was developed, offering a promising avenue for utilizing cellulose-based materials in the selective separation of natural products.

Molecular dynamics simulation of the interaction between aggregates and calcium silicate hydrate and influence of ethylene vinyl acetate copolymer modifier

ABSTRACT It is known that the bonding strength of the aggregate/cement interface affects the overall durability of concrete. However, whether the modification of ethylene vinyl acetate (EVA) copolymer affects the interface interaction between aggregates and cementitious materials is unclear. This study analyzed the interface's static structure, dynamic characteristics, and binding energy. The interaction mechanisms between acid and alkali aggregates and hydrated calcium silicate and the modification effect of EVA were compared. The calculation results of relative density distribution and radial distribution function verified the difference in the structure of EVA-modified acidic or alkaline interfaces. EVA polymer chains significantly blocked the flow of Ca atoms in CaO at the CaO/C-S-H interface and weakened the van der Waals effect at the interface. The mean square displacement and time correlation function analysis indicate that all unmodified interfaces have stable interface structures. After EVA modification, the stability of CaCa-HW decreased significantly, hindered the generation of hydration products, and verified the weak Ca atom transport at the CaO/C-S-H interface. In addition, the adhesion energy of SiO2/C-S-H and CaO/C-S-H after EVA modification decreased by 6% and 14.8%, respectively, quantifying the modification effect of EVA.

Synthesis, spectroscopic analysis (FT-IR, FT-Raman, UV, NMR), non-covalent interactions (RDG, IGM) and dynamic simulation on Bis(8‑hydroxy quinoline) salicylate salicylic acid

Using spectrum techniques and density functional theory (DFT) reckonings, structural, vibrational and electrical characteristics of Bis(8‑hydroxy quinoline) salicylate salicylic acid (8HQSA) were determined. Characterizing the chemical under inquiry involved employing FT-IR, FT-Raman, UV–vis spectral studies and single crystal X-ray diffraction (SCXRD). For the characterization, the B3LYP approach inside the structure of DFT was employed, with a 6–311++G(d,p) basis set. The structural study shows that the stability of 8HQSA crystalline structure arising from N–H⋯O, C–O⋯H and O–H⋯O hydrogen bonding interactions. The 1H and 13C NMR chemical shifts were calculated using Gauge Independent Atomic Orbital (GIAO) technical. Vibrational frequencies and molecular geometry were computed and likened with experimental data. Here, non-covalent interactions were deeply analyzed in terms of topological parameters (AIM), electron localization function (ELF), localized orbital locator (LOL), Hirshfeld surface and reduced density gradient (RDG) method. Weak interactions such as H-bonds, van der Waals and steric effect in 8HQSA were visualized and quantified by the independent gradient density (IGM) based on the trimolecular density. The hyper-conjugative and the delocalization of charge in 8HQSA have been elucidated by natural bonding orbital (NBO) while its chemical reactivity was studied and discussed by using molecular electrostatic potential surface (MEP), frontier molecular orbital (FMOs), density of state (DOS) and partial density of state (PDOS). The positions of the molecule's nucleophilic and electrophilic groups were ascertained using Fukui analysis. To describe the size, structure, and reactive sites of the molecules, the molecular electrostatic potential and total electron density are calculated. With a band gap (2.58 eV), FMO study indicates that the material is both bioactive and stable. The ADMET factor and drug similarity are used to predict 8HQSA's pharmokinetic characteristics. Based on the findings, it can be concluded that the 8HQSA particle is optimally crystallised and recommended as a preventative measure against bacterial and fungal infections. The stability of the title compound has been investigated via molecular dynamics simulations. In-vitro antimicrobial activity results clearly reveal that in all the four strains, activity increases with increase in compound concentration and the inhibition of the strains also increases. From both molecular docking and In-vitro Antimicrobial Activity the title compound can be certified that it inhibits antimicrobial activity.

Effect of densification process on mechanical enhancement of graphene laminates

Graphene nanosheets have attracted great attention in the field of nanotechnology applications due to their extraordinary mechanical properties. While the structural defects such as gaps will occur during the preparation of graphene laminates, which will greatly damage the performance of the macroscopic material. Hence, a simple and promising mechanical compression method is used to improve the mechanical properties of graphene laminates. However, the roles of the densification process in the mechanical enhancement mechanism of graphene laminates are not clear. In our work, the mechanical enhancement of the compressed graphene (PG) laminates was investigated by the coarse-grained molecular dynamics simulation method. The tensile strength of PG model could be increased by increasing the graphene nanosheet size and the degree of compression in the system. And the model has the stronger van der Waals effect between graphene sheets due to the larger graphene size as well as the higher overlap ratio. Furthermore, two kinds of PG laminates were prepared by densification method, and the tensile strength was consistent with the upward trend of the PG model. This work provides an in-depth understanding on the mechanical enhancement of the densification process and lays a foundation for the future practical application of graphene laminates.

Effect of temperature on interface debonding behavior of graphene/graphene-oxide on cement-based composites

Temperature effect easily affect the adhesion of graphene/graphene oxide (GO) on the cement-based composites originating from the weaker non-covalent bonding at the interface, leading to weakening of the cementitious composite properties. In this study, the interfacial debonding behavior of graphene/GO and cement-based composites was investigated for low to high temperatures (250∼550 K) using controlled molecular dynamics simulations. The maximum tensile force and work of adhesion both decrease with increasing temperature, and the value of GO is 5∼6 times that of graphene. Especially at the high temperature end, GO is still difficult to peel off (Fmax: 7.93×103 pN, Wmax:2129.60 Kcal/mol). Meanwhile, the insights into the distribution and concentration of functional groups have shown that high concentrations and edge functional groups can improve interface adhesion. Energy decomposition demonstrated that, compared to the Coulomb effect of charge and the prestress of surface wrinkles, the van der Waals effect plays a major role in interface adhesion. Entropy analysis further reveals the high temperature sensitivity of graphene and the low sensitivity of GO due to edge functional groups. We believe that the insight into the temperature effect of interface debonding behavior at nanoscale can provide theoretical support for the effective temperature working conditions of graphene/graphene-oxide on cement-based composites.

Preparation of tannic acid-reinforced cellulose nanofiber composites for all-water-based high-performance wood adhesives

Traditional adhesives easily release toxic gases during the preparation process or apply to wood composite products, which have adverse effects on the human body and the environment. Herein, an all-water-based high-performance wood adhesive is prepared using TEMPO-oxidized cellulose nanofiber (TOCNF), acrylamide (AM), and tannic acid (TA) through free radical polymerization. Different characteristics of the prepared composites, including morphology, injectability, and adhesion properties, have been investigated. Results showed that the TA/TOCNF/PAM composite has excellent injectability. The addition of TA can enhance the lap shear strength of the TA/TOCNF/PAM composites and with the increment of TA content, the lap shear strength gradually decreases. The formation of effective hydrogen bonds and Van der Waals interaction among the rich functional groups in the composite, lead to strong lap shear strength on different substrates. The composite with 5.0 g of AM, 5.0 g of the TOCNF suspension and 0.1 g TA possesses a high lap shear strength of 10.5 MPa on wood and 1.5 MPa on aluminium. Based on strong adhesion properties and excellent injectability, the TA/TOCNF/PAM composites have great potential in the furniture construction and building industries.

General Separation of Carbon Dots by Polyamide Chromatography.

Carbon dot (C-dot) separation/purification is not only a fundamental chemical issue but also an essential precondition for revealing C-dots' true nature. To date, adequate separation of C-dots has remained an open question due to the lack of an appropriate fine separation system. Herein, we discover and reveal that polyamide chromatography can provide versatile and powerful performances for C-dot separation. By a joint study of experiments and all-atom molecular dynamics simulations, we demonstrate that multiple interaction forces, including electrostatic repulsion/attraction, hydrogen bond, and van der Waals effects, exist simultaneously among the stationary phase, mobile phase, and the separated C-dots. Furthermore, the magnitude of these forces is dependent on the surface chemistry of the separated C-dots and the nature of the used mobile phases, providing a theoretical basis and experimental operability for C-dot separation. So, the proposed system possesses the capacity for adequately separating hydrophilic, amphiphilic, and lipophilic C-dots. The polyamide chromatography, due to its versatile and powerful separation performances, not only provides more thorough separation effects but also helps to correct our false perceptions from inadequate purified C-dots.

Refinement of Docked Protein-Protein Complexes Using Repulsive Scaling Replica Exchange Simulations.

Accurate prediction and evaluation of protein-protein complex structures is of major importance to understand the cellular interactome. Predicted complex structures based on deep learning approaches or traditional docking methods require often structural refinement and rescoring for realistic evaluation. Standard molecular dynamics (MD) simulations are time-consuming and often do not structurally improve docking solutions. Better refinement can be achieved with our recently developed replica-exchange-based scheme employing different levels of repulsive biasing between proteins in each replica simulation (RS-REMD). The bias acts specifically on the intermolecular interactions based on an increase in effective pairwise van der Waals radii without changing interactions within each protein or with the solvent. It allows for an improvement of the predicted protein-protein complex structure and simultaneous realistic free energy scoring of protein-protein complexes. The setup of RS-REMD simulations is described in detail including the application on two examples (all necessary scripts and input files can be obtained from https://gitlab.com/TillCyrill/mmib ).

Transforming roasted sesame oil into oil-impregnated powder: Avant-garde plating technique in molecular cooking - Mechanisms, physicochemical properties, and quantitative release of odorant-active compounds

Plating, which involves converting liquid oils into oil-impregnated powders, is one of the techniques employed in molecular cooking. This study examined the oil holding capacity and mechanisms, physicochemical properties, and quantitative release of key odorant compounds of plated roasted sesame oil-impregnated powders. The plated oil powders were prepared with nutty-flavored roasted sesame oil and two commercial plating agents; Pine Flow (PF) and N-Zorbit 2144 (NZ). PF and NZ had distinctly different morphologies and physical properties. PF had a higher porosity, intrusion volume, and oil holding capacity than NZ. The oil holding capacities of NZ and PF were 1.35 and 3.44 g/g (oil to plating agent), respectively. The FT-IR data indicated that hydrogen bond, hydrophobic interaction, and van der Waals effect were responsible for the loading the oil onto the plating agents. The plated oil powders were efficient carriers for key odorants, releasing a high portion of volatiles up to 84% after adding water (simulated saliva). This study is the first to report on the physicochemical properties, oil-holding mechanisms, and quantitative information on the aroma release of plated oil powders as a flavored-oil carrier, which could be useful in molecular cooking and the food industry.

The Calculation of Both Electrostatic and Van der Waals Effects to Probe the Efficiency of Solvent Extraction of Heterocyclic Aromatics from Heavy Oil.

Due to the complex composition and similar structure, the extraction denitrification of aromatic rich oil is faced with the contradiction problem of denitrification efficiency and aromatic loss which cannot be efficiently solved by experiments. However, the complex interactions involved can be analyzed from the perspective of calculation, and the prediction criteria and methods are proposed. Based on rigorous density functional theory calculation data, Simple models based on electrostatic potential (ESP) and Van der Waals potential (VdWP)-based calculations were established and validated. The twofold model provided the best prediction for interactions between extractants and nitrogen compounds and between extractants and aromatics, which determines denitrification efficiency and aromatic loss, respectively, due to the most complete description of both electrostatic and VdW force. This provides a powerful tool for evaluating the non-covalent interactions and thence tuning the efficiency of the separation process. Thus, high denitrification efficiency (43.2~66.3 %) and moderate aromatic loss (1.7~4.4 %) were obtained using screened deep eutectic solvents (DESs). This ideal observation provided the potential for mild hydrodesulfurization and manufacture of high-grade carbon materials.

Insights into the effects of zeolite structural confinement on pentene catalytic cracking to light olefins

It has long been known that the structural and topological diversity of microporous voids confer significant catalytic diversity to zeolites. What is less understood, however, is the insights into the role of confinement on reactivity of important reactions such as alkene cracking and hydrogen transfer. The influence of confinement environment toward the reaction process on conversion of pentene is the focus of this study. Pentene is mainly converted through the reaction of hydrogen transfer, dimerization cracking and monomolecular cracking. The more effective van der Waals stabilization within smaller voids leads to lower enthalpies, and the transition state of monomolecular cracking retain higher entropies, which makes monomolecular cracking dominant in F-ZSM-5 at high temperature. It is therefore favorable for the enhancement of ethene selectivity in the cracking products. Furthermore, the tighter confinement could strengthen the adsorption ability and weaken the CC bonds of pentene, which results in prominently enhanced rate of pentene monomolecular cracking, as suggested by the kinetic analysis and density functional theory (DFT) simulation.

Mechanism of [BMIM][BF4] inhibiting coal groups activity from experiments and DFT calculations

The interaction between ionic liquid and coal (IL-coal) plays a theoretically pivotal role in revealing the internal mechanism of ILs inhibiting coal spontaneous combustion (CSC). This can determine the degree of reaction or inhibitory ability between IL-coal molecules. First, the activity characteristics of FTIR structural parameters from molecular surfaces affected by [BMIM][BF4] were obtained. In addition, the optimal structures of [BMIM][BF4] with methyl, hydroxyl, ether bond, methylene, and carboxyl groups were determined based upon Density Functional Theory. The activity characteristics of the IL-coal complexes were investigated from the aspects of charge population and transfer, bond length change, and electrostatic potential distribution. Finally, the types and relationships of the forces between the five structures of the IL-coal complexes and the stability and activity order were explored. The results demonstrated that [BMIM][BF4] could possibly reduce the structural abundance, side chain length, and oxygen-containing groups of aliphatic hydrocarbons. The interaction between anion [BF4]− and active groups was more stable than that between cation [BMIM]+ and active groups. Meanwhile, the dissolution and destruction of coal active groups by ILs were not completely determined by the number of hydrogen bonds formed between ILs and coal active groups, but by the strength of hydrogen bonds formed between anions and coal active groups, and the effect of anions was stronger than that of cations. The order of oxidation capacity of the IL-coal complexes was: [BMIM][BF4]–CH2– > [BMIM][BF4]–O– > [BMIM][BF4]–COOH > [BMIM][BF4]–CH3 > [BMIM][BF4]–OH. The van der Waals effect mainly presented complexes. Despite this, there were hydrogen bonds between the complexes formed by hydroxyl groups, but the hydrogen bond force showed exceptionally slight effects.

Extraction of rubidium and cesium from oilfield brine by the two-step adsorption–flotation method

Rb, Cs, and their compounds are important raw materials, and the extraction of Rb+/Cs+ from brine has attracted increasing attention. In this work, the extraction of Rb+/Cs+ from aqueous solutions, such as oilfield brine, through an adsorption–flotation process was evaluated. The effects of various factors on the extraction efficiency (Ee) of Rb+/Cs+ and the floatability of particulate matter were systematically investigated, and the Ee of Rb+/Cs+ was maintained at approximately 80% after five cycles. Because of the difference in the selectivity of ammonium molybdophosphate (AMP) for Rb+ and Cs+, Rb+/Cs+ can be extracted from oilfield brine using a two-step adsorption–flotation process. The Ee values of Rb+ and Cs+ were 18.01% and 90.83%, respectively, in the first step and 80.10% and 8.22%, respectively, in the second step. The adsorption and flotation mechanisms were analyzed using density functional theory (DFT), fourier transform infrared (FT-IR) spectroscopy, and point of zero charge (PZC). The adsorption mechanism could be explained by electrostatic interactions and van der Waals effects between the ions and molybdophosphate, and the flotation mechanism was mainly the electrostatic interaction between the CTAB cations and rubidium molybdophosphate (RMP)/cesium molybdophosphate (CMP) particles.

Transport properties in liquids from first-principles: The case of liquid water and liquid argon.

Shear and bulk viscosities of liquid water and argon are evaluated from first-principles in the density functional theory (DFT) framework, by performing molecular dynamics simulations in the NVE ensemble and using the Kubo-Greenwood equilibrium approach. The standard DFT functional is corrected in such a way to allow for a reasonable description of van der Waals effects. For liquid argon, the thermal conductivity has been also calculated. Concerning liquid water, to our knowledge, this is the first estimate of the bulk viscosity and of the shear-viscosity/bulk-viscosity ratio from first-principles. By analyzing our results, we can conclude that our first-principles simulations, performed at a nominal average temperature of 366 to guarantee that the systems are liquid-like, actually describe the basic dynamical properties of liquid water at about 330K. In comparison with liquid water, the normal, monatomic liquid Ar is characterized by a much smaller bulk-viscosity/shear-viscosity ratio (close to unity) and this feature is well reproduced by our first-principles approach, which predicts a value of the ratio in better agreement with experimental reference data than that obtained using the empirical Lennard-Jones potential. The computed thermal conductivity of liquid argon is also in good agreement with the experimental value.

Van der Waals Black Phosphorus/Bi10O6S9 Heterojunction Harvesting Ambient Electric Field Energy for Enhanced Photoelectrochemical Sense

Ingenious utilization of ambient energy is a vigorous issue for heterostructure-type devices in evoking their performance in various applications. Using the van der Waals effect, two-dimensional black phosphorus is developed to bond with a unique Bi10O6S9 layer, which then forms a type-II heterostructure based on a truncated pyramidal Si/Ag/WO3 substrate. It is demonstrated that the ambient electric field can not only promote the separation and transfer of the electrons (and holes) excited by light irradiation but also induce additional electrons (and holes) to migrate in the same direction as that of those excited by light irradiation. Under the action of a 1100 V m–1 ambient electric field, the photoelectrochemical response current of light irradiation is increased 1.6 times, while the stability of the photoelectrochemical response current can retain 81.06% of the initial value even after 6000 s. The thin black phosphorus layer alone contributes 1.75 times the response current. On this basis, a sensitive device for monitoring the weak physiological electric field of a human arm assisted by light irradiation was developed, which shows wide application prospects in wearable devices.

Anti-icing mechanism of an environmentally sustainable tenebrio molitor antifreeze protein modified asphalt binder via molecular dynamics simulations

Environmentally friendly and available tenebrio molitor antifreeze protein (TmAFP) is capable of retarding ice growth. For optimally automatic anti-icing performance in asphalt pavement, environmentally sustainable TmAFP modified asphalt binder is innovatively proposed. Anti-icing feasibility of TmAFP modified asphalt binder is comprehensively investigated via molecular dynamics (MD) simulations including conformational stability, melting temperature, inhibition effect of ice growth and binding free energy between TmAFP and asphalt molecules in various temperatures. It is the first attempt that fully atomistic molecular dynamics simulations on the TmAFP modified asphalt binder are conducted, indicating that the stable binding of TmAFP to ice is attributed to hydrogen bonds originating from the hydroxyl group in the side chain carboxyl group of the threonine (Thr) residue and the amine group of the cysteine (Cys) residue in the β-sheets of TmAFP. Meanwhile, Gibbs-Thomson effect is also observed in the Ice-TmAFP-Water system, which contributes to retard ice growth. The calculation of binding free energy has revealed that TmAFP has the greatest affinity with resin in asphalt molecules, followed by asphaltene and saturation. Furthermore, the van der Waals effect and non-polar interactions are the main contributors to the binding stability of TmAFP and asphalt molecules. Overall, the results provide an efficient avenue to design the preparation of environmentally sustainable TmAFP modified asphalt binder in the laboratory, which have great potential in designing high-performance automatic anti-icing asphalt pavement.

Molecular dynamics simulation on the rejuvenation effects of waste cooking oil on aged asphalt binder

Waste cooking oil (WCO) has received attention on rejuvenating aged asphalt binder widely in recent years. This study evaluated the rejuvenation effects of WCO on aged asphalt binder on the micro-scale using molecular dynamics (MD) simulation. First, the representative molecules of WCO and asphalt binders were selected. The molecular mixture model was then developed. The thermodynamic properties were investigated, including density, cohesive energy density, solubility parameter, and surface free energy. The results show that WCO can restore the thermodynamic properties of aged asphalt binder to some extent and WCO has different influences on electrostatic interactions and van der Waals effects. From the diffusion behavior and molecular structure of asphalt binder, WCO can improve the molecular mobility and restore the colloidal structure. Besides, the adhesion work and moisture susceptibility of asphalt binder-aggregate interfaces (calcite and quartz) were evaluated. The results show that WCO can improve adhesion work between asphalt binder and aggregates since WCO can change molecular structure of asphalt binders and certain adhesion work exists between WCO and aggregates. Also, it can mitigate the moisture susceptibility of asphalt binder-aggregate interfaces (calcite and quartz). The study demonstrates that the MD simulation can help to understand the rejuvenation effects of WCO on aged asphalt binder on the micro-scale. • WCO can improve the mobility of the saturates best of aged asphalt binder. • WCO can weaken both the self-aggregation of asphaltenes and interactions between asphaltenes and saturates. • WCO can change the molecular structure of asphalt binders.

Electric Field Screening in Gate‐Tunable van der Waals 2D‐Metal/InSe Junctions

AbstractThe prediction of the dielectric response in 2D metal–semiconductor junctions (MSJs) is challenging since the screening is inhomogeneous. Herein, a generalized model is proposed to uncover the relationship between interfacial electrostatic screening and the modulation of Schottky barrier height (ΦSB) in 2D MSJs. This model is developed based on the effective dielectric constant, interfacial distance, and van der Waals gap that sheds light on the profound difference between dielectric screening in 2D and conventional MSJs. This model can predict the variation of ΦSB for a series of 2D MSJs. Combining thermionic field emission theory with the model, several compatible 2D metals are provided for low‐dimensional electronics, among which the α‐graphyne‐based junction exhibits the largest on/off ratio.

Terahertz spectral vibrational properties and weak interactions analysis of caffeic acid and ferulic acid

Caffeic acid and its derivative, ferulic acid, are a class of natural phenolic compounds with strong antioxidant properties and have good application prospects in the field of medicine. In this paper, the spectral characteristics and the types of intermolecular interactions of caffeic acid and ferulic acid were analyzed using terahertz (THz) detection method combined with quantum chemical correlation analysis methods. The absorption spectra of caffeic acid and ferulic acid in the 0.4–2.0 THz band were measured by terahertz time-domain spectroscopy (THz-TDS) detection system. The theoretical spectra of caffeic acid and ferulic acid in this band were simulated by structure optimization and frequency calculation with the help of density functional theory (DFT), and the theoretical and experimental spectra were in good agreement. To resolve the spectral information in detail, we used the Potential Energy Distribution (PED) method to assign the vibrational modes of the absorption peaks, then identified the types of intermolecular interactions by interaction region indicator (IRI) and energy decomposition analysis based on forcefield (EDA-FF) methods to explain the reasons for the formation of vibrations. The results show that the main vibrational modes of caffeic acid in the absorption peak are dihedral torsion, for ferulic acid are bond angle bending and dihedral torsion. Intermolecular interactions play an important role in these vibrations, with van der Waals effects predominant, while the intermolecular hydrogen bonding model overall vibrates. This work demonstrates that using THz spectroscopy combined with DFT, IRI, and EDA-FF methods, can analyze the weak interaction types of structurally similar substances efficiently.