Values Of Vibrational Frequencies Research Articles

Synthesis and spectroscopic characterization of 2-furancarbothioamide: N-(4-fluorophenyl)furan-2-carbothioamide

This investigation deals with an alternative thionation synthetic strategy for the preparation of N-(4-fluorophenyl)furan-2-carbothioamide using elemental sulphur and applying the Willgerodt-Kindler reaction. The carbothioamide was obtained with ca 30 % yield assessing the purity (higher than 90 %) with GC/MS spectrometry, and the compound was fully characterised by NMR (1H, 13C), FTIR and UV–visible spectroscopies. Indeed, 1H NMR spectroscopic analysis demonstrated that a single conformer with anti-anti geometry was formed attributed to the observation of only one N-H signal (9.37 ppm) of the NH-C=S group and, FTIR spectroscopy (N-H stretching at 3372 cm−1) also reinforces this observation. UV-visible absorption and fluorescence emission spectra were recorded in different polar and nonpolar solvents (acetonitrile, ethanol and n-heptane) and the λ0,0 cross point displays a bathochromic shift of 11 nm with the increasing solvent polarity. The fluorescence quantum yield (ϕf) has been measured at room temperature concluding that this carbothioamide derivative is not a fluorescent compound showing a ϕf value of 0.0002. Finally, theoretical calculations have been carried out to estimate the NMR chemical shifts as well as vibrational frequencies values of the anti-anti isomer and these values were compared with the experimental data obtaining satisfactorily correlations.

Intermolecular interaction of azide, cyano and alkyne-N-phenethylacetamide dimers: Experimental and quantum chemical approach

In this study, we present the synthesis and structure characterization by single-crystal X-ray Diffraction (SC-XRD), Ultraviolet Spectroscopy (UV), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) and High-resolution Mass Spectrometry (HRMS) of 2-azido-N-phenethylacetamide (4) and 2-cyano-N-phenethylacetamide (6). Further, Density Functional Theory (DFT) was employed to get a better insight regarding the properties exhibited by the compounds. The computational chemistry has been used to explain and investigate the bimolecular nucleophilic substitution (SN2) and concerted acyl substitution mechanisms for the synthesis of compounds 4 and 6, respectively. Additionally, intrinsic reaction coordinate (IRC) calculations confirm the transition state for these reactions. The X-ray diffraction analysis showed that the compounds 4 and 6 crystallized as monoclinic systems, in space group P21/c and P21/n, respectively. The Hirshfeld Surface Analysis revealed that the main contributions in the crystal packing have H···H, H···N/N···H, H···C/C···H and H···O/O···H interactions. The frontier molecular orbital energies were calculated and the HOMO-LUMO energy gap of 4 and 6 were 10.011 and 10.278 eV, respectively. Theoretical values of electronic transitions, vibrational frequencies and NMR chemical shifts were calculated and compared with experimental results, they all showed good results.

Influences of fatigue stiffness degradation of in-service concrete T-beams on natural vibration frequency

ABSTRACT In order to obtain the fatigue stiffness degradation law of in-service concrete T-beam and carry out fatigue life prediction, a dual-stage stiffness degradation model considering cracks was established for T-beams and formulas for calculating the fundamental frequency of damaged concrete T-beams were deduced based on relevant theories of damage mechanics. The developed model aimed to investigate the influences of the fatigue stiffness degradation of in-service concrete T-beams on the natural vibration frequency of structures. A fatigue test was conducted for full-scale test beams to examine the crack development and fundamental frequency change law of structures during the fatigue process. Based on a full scale model of 10 m reinforced concrete T-beams, static and fatigue failure tests were carried out to obtain the evolution law of fatigue residual stiffness with load times. Fatigue damage coefficient D and stiffness degradation coefficient k were introduced to establish the fatigue life prediction model of T-beams in service. In line with the related test data and fundamental frequency formulas, stiffness updating methods were put forward for the concrete T-beam finite element models. By comparing the calculated value and test value of the natural vibration frequency of structures, the relative error was estimated to be within 6%. This verified the accuracy and reliability of the fundamental frequency calculation formulas and the updated finite element models. The research results can be used as a reference for the precise simulation of the fatigue damage finite element models of concrete T-beams. Finally, a method for life prediction of in-service reinforced concrete beam Bridges is proposed, and relevant research results can provide theoretical support for the study of life prediction of such Bridges.

Blasting vibration hazard classification and prediction research

This paper explores the hazard classification method of blasting vibration on nearby buildings. The ratio of the self-vibration frequency f0 of the protected buildings to the main vibration frequency f of blasting vibration and the ratio of the actual measured peak blasting vibration velocity to the permissible vibration velocity of blasting safety regulations are used as two indicators of the blasting vibration hazard classification method, the blasting vibration hazard index calculation formula was proposed, and the blasting vibration hazard was classified into four levels according to the blasting vibration hazard index. An open pit mine blasting project was used for monitoring, the collected data were processed by random forest method. After processing, bursting heart distance, the total explosive quantity required for one blast, the hole distance meter delay, and the row distance meter delay was selected as the input parameters; the optimal kernel function parameter gamma and c were applied to the SVR (Support Vector Regression) model by changing the search step to expand the parameter search, and improved GS-SVR (Grid Search-Support Vector Regression) model was constructed, through which peak blasting vibration velocity and vibration frequency values were predicted. The results show: improved GS-SVR is effective in predicting peak blasting vibration velocity, with the lowest relative error of 0.15% and the average error of 7.96%; the minimum relative error for the prediction of vibration frequency is 0.03% and the average error is 2.54%. The measured data in the literature of related scholars verified that the blasting vibration hazard classification method is scientific and feasible. It can provide reference and reference for blasting vibration hazard classification and prediction of similar blasting projects.

Assessment of termite damage in cross-laminated timber sections using micro-computed tomography and vibration analysis

The durability of engineered wood products (EWPs) is a parameter yet to be fully investigated and understood. This is specifically important for mass timber structures and cross-laminated timber (CLT) panels. The effect of termites and scale of damage on radiata pine sawn boards have been previously investigated. However, the effects of glue line and the layered structure of CLT exposed to termite feeding in the field in Australia have not been studied. A total of 420 CLT specimens with different exposed faces and layer arrangements were exposed to termite attack in the field. Microcomputer tomography and vibration analysis were used to assess sample conditions before and after 20 weeks exposure. The observed changes showed damage patterns within samples where a glue line and different growth ring patterns were present. The termites created continuous damage along the longitudinal cells through the length and width of the samples. The 3D data showed that the edge gap on the face of panels could potentially act as a pathway for termites entering the core or mid-layers of the panel. The vibration frequency values were lower for samples after the termite exposure. The vibration analysis results showed significant effects of sample direction exposed to termite attack, and percentage of mass loss had significant effects on internal friction and damping values determined.

Infrared and Raman vibrational modelling of β-C2S and C3S compounds

Density Functional Theory was applied to obtain a refined IR and Raman theoretical vibrational spectra of the major silicate phases of Portland cement, i.e. dicalcium silicate (β-C2S) and tricalcium silicate (C3S). We investigate the crystal structure and vibrational frequency values in the electronic ground state using a plane wave density functional method with new norm-conserving pseudopotentials. The calculated results show that the optimized geometry can reproduce the crystal structure well, and the theoretical vibrational frequency values show good agreement with the experimental values and allow us to describe some uncertainties in the experimental assignments previously described. The assignment performed for 100–1200 cm−1 region shows that the vibrations of C2S and C3S are presented in the IR spectra, while the vibrations with a minor contribution from the silica groups are observed in the Raman spectra. Satellite bands from C3S are observed in the experimental spectra but there not in the calculated one.

Finite element mesh refinement for in-plane and out-of-plane vibration of variable geometrical Timoshenko beams based on superconvergent vibration modes

PurposeIn this paper, a superconvergent patch recovery method is proposed for superconvergent solutions of modes in the finite element post-processing stage of variable geometrical Timoshenko beams. The proposed superconvergent patch recovery method improves the solution speed and accuracy of the finite element analysis of a curved beam. The free vibration and natural frequency of the beam were considered for studying forced vibrations and structural resonance. Beam vibration mode analysis was performed for high-precision vibration mode solutions and frequency values. The proposed method can be used to compute beam vibration modes of beams with different shapes and boundary conditions as well as variable cross sections and curvatures. The purpose of this paper is to address these issues.Design/methodology/approachAn adaptive method was proposed to analyse the in-plane and out-of-plane free vibrations of the variable geometrical Timoshenko beams. In the post-processing stage of the displacement-based finite element method, the superconvergent patch recovery method and high-order shape function interpolation technique were used to obtain the superconvergent solution of mode (displacement). The superconvergent solution of mode was used to estimate the error of the finite element solution of mode in the energy form under the current mesh. Furthermore, an adaptive mesh refinement was proposed by mesh subdivision to derive an optimised mesh and accurate finite element solution to meet the preset error tolerance.FindingsThe results computed using the proposed algorithm were in good agreement with those computed using other high-precision algorithms, thus validating the accuracy of the proposed algorithm for beam analysis. The numerical analysis of parabolic curved beams, beams with variable cross sections and curvatures, elliptically curved beams and circularly curved beams helped verify that the solutions of frequencies were consistent with the results obtained using other specially developed methods. The proposed method is well suited for the mesh refinement analysis of a curved beam structure for analysing the changes in high-order vibration mode. The parts where the vibration mode changed significantly were locally densified; a relatively fine mesh division was adopted that validated the reliability of the mesh optimisation processing of the proposed algorithm.Originality/valueThe proposed algorithm can obtain high-precision vibration solutions of variable geometrical Timoshenko beams based on more optimized and reasonable meshes than the conventional finite element method. Furthermore, it can be used for vibration problems of parabolic curved beams, beams with variable cross sections and curvatures, elliptically curved beams and circularly curved beams. The proposed algorithm can be extended for application in superconvergent computation and adaptive analysis of finite element solutions of general structures and solid deformation fields and used for adaptive analysis of more complex plates, shells and three-dimensional structures. Additionally, this method can analyse the vibration and stability of curved members with crack damage to obtain high-precision vibration modes and instability modes under damage defects.

Theoretical (B3lyp) and Spectroscopic (Ft-Ir, 1h-Nmr and 13c-Nmr) Investigation of 2- Methoxy-6-[(3-(P-Methylbenzyl)-4,5-Dihydro-1h-1,2,4-Triazol-5-One-4-Yl)-Azomethin]-Phenyl Benzoate

Density functional theory (DFT) is an inexpensive approach used to study the molecular structure, many theoretical properties, biological activities and electronic properties of simple and complex compounds. In this study, the all quantum chemical studies of 2-Methoxy-6-[(3-(p-methylbenzyl)-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl)-azomethin]-phenyl Benzoate molecule were calculated using the DFT(B3LYP) method with 6-311++G(d,p) basis set. For use in all these computational processes, initially the molecule was optimized. Thus, the most stable state of atoms was reached. Then, the calculations of carbon-13 and proton-NMR isotropic shift values were performed in the solvent (DMSO) and gaseous with "the gauge-independent atomic orbital" (GIAO). Infrared (FT-IR) vibration frequency values were calculated from the Veda4f program. The theoretical vibration frequency values were compared with the experimental IR values. Experimental data obtained from the literature. In addition, the electronic properties (chemical hardness and softness, ionization potential (I), electronegativity (χ), electron affinity (A), electrophilic and nucleophilic index), ΔEg energy gap, HOMO-LUMO energies, the geometric properties (bond angle and length), the thermodynamic properties (thermal capacity (CV), entropy (S), thermal energy (E), dipole moment, mulliken atomic charge values, molecular electron potential (MEP), total density and contour surface maps and the total energy of the molecule were determined.

Проектирование силовых конструкций с использованием топологической оптимизации и технологии аддитивного производства

The aim of the work is to create an integrated technology for designing load-bearing structures using topological optimization and additive manufacturing, as well as its approbation on the example of a specific task of designing and manufacturing an aerospace structure. The proposed methodology describes the main design stages for additive manufacturing. In the ANSYS system, the power scheme of the structure is designed based on topological optimization. To refine the dimensions and shape of the structural strength elements, a module was used that allows optimizing the geometric model of the structure by shifting the nodes of the design grid of the structure. The results of the verification calculation showed that the designed structure has a significantly lower mass compared to the prototype and is not inferior to it in terms of rigidity, strength and minimum values of natural vibration frequencies. The article describes the implementation of the production process for creating a workpiece using selective laser melting technology. The development of a 3D model of the design sample was carried out in the Siemens NX software. For the considered design, the method of residual stress compensation based on the optimization of heat sinks on the technological construction platform and the method of preliminary correction of the workpiece geometry in the SimufactAdditive software were applied. The results obtained in the work show the possibility of introducing additive manufacturing together with topological optimization in the design of spacecraft, including the load-bearing structures of their propulsion systems.

Thermal Vibration of Thick FGM Circular Cylindrical Shells by Using TSDT

The generalized differential quadrature (GDQ) method is used to study the thermal vibration of thick functionally graded material (FGM) circular cylindrical shells. The nonlinear coefficient effect of third-order shear deformation theory (TSDT) model of displacements on the thermal equations of motion is considered. The parametric effects of FGM power law index and environment temperature on the time responses of stresses and displacements are considered. The linear varied effect of shear correction coefficients on the calculation of stiffness integration is also considered. The simply homogeneous equation is used to find the values of vibration frequency, also the dynamic GDQ discrete equation in matrix form are used to find the values of time response and transient response for the thick FGM circular cylindrical shells.

STRENGTH AND STABILITY ASSESSMENT OF NPP REINFORCED CONCRETE STRUCTURES REGARDING THE RESULTS OF VIBRATION ANALYSIS

Introduction . The article outlines methodological stages when assessing the resource of nuclear power plant (NPP) operation units with regard to degradation in the dynamic characteristics of reinforced concrete structures obtained by means of vibration analysis methods on the example of hot cells of nuclear installations. Aim : to improve the method currently used for assessing the stress-stain behavior and strength of NPP structures regarding the aging process of reinforced concrete elements under various environmental exposures. Materials and methods . A methodology is proposed for assessing the strength (loading capacity) and stability of NPP structures where significant variations in the properties of reinforced concrete elements have taken place under the action of continuous operation and thermal mode disturbances, thus weakening the element stiffness and, as a result, reducing their strength and stability. Therefore, in order to evaluate the stress-stain behavior and strength of hot cells, calculations should be carried out taking into account the history of structure loading and the process of crack development over the entire operation period. However, no analysis of the history of thermal loading has been performed during the operation period of the NPP under study. In addition, there is a lack of suitable software packages for nonlinear dynamic analysis certified by Rostechnadzor capable of considering the loading history and crack development in reinforced concrete structures. In order to eliminate the mentioned shortcomings, a vibration analysis of the walls and floors of hot cells should be performed to determine the following dynamic characteristics: natural vibration frequency and mode, logarithmic decrement of damping, deformation modulus and Poisson ratio for each wall and floor. Further, based on the obtained experimental data, the stress-stain behavior and strength of hot cells should be calculated using experimental data as calculation input information. The calculation methodology is based on a nonclassical method of modal superposition using the ABAQUS, ANSYS, and Nastran software packages. In order to verify the correctness of the results obtained by vibration analysis, an assessment of floor dynamic characteristics at the point +13.450 in the “П”–“Ж” rows was conducted. Results . The values of deformation modulus and natural vibration frequency obtained in the conducted experiment were found to agree with the calculated values. Conclusions . A methodology for assessing the strength of NPP structures regarding the aging of reinforced concrete under various environmental exposures was presented. The validity of dynamic characteristics obtained using vibration analysis was evaluated.

Natural Vibration Characteristics Analysis of a High-Rise Reinforced Masonry Structure Based on Field Test Data

In structural response array observation, the vibration response of a structure during an earthquake or from the natural environment is recorded and stored using high-sensitivity strong motion seismographs, and the dynamic characteristics of the structure are analyzed and determined using random signal data processing technology. Due to the use of field test data for analysis, this may be the most accurate and effective way to obtain the actual characteristics of the structure, which can be further used to verify the accuracy of theoretical analysis, experimental results, and numerical simulations. Therefore, this technique plays an important role in earthquake prevention and disaster reduction, with the application of strong motion observation data. In this paper, field vibration tests were performed on the highest reinforced masonry structure in China. With the test environmental vibration data, the natural vibration frequency values and mode shapes of the structure were identified using the peak picking method. A numerical modal analysis was then performed to verify the accuracy of the field test results. In addition, the structural response records obtained during an earthquakes in Songyuan were also used to identify the natural vibration frequency of the structure and the changes in the natural vibration frequency before, during, and after the earthquake. The results showed that the structure was not damaged during the earthquake and remained in an elastic state.

Caracterización y evaluación de colorantes de Monnina vargassi y Vaccinium floribundum por espectroscopia infrarroja FTIR-ATR y UV Visible

Polyphenols and anthocyanins have been determined in fresh native fruits of Vaccinium floribundum and Monnina vargassi, for which their pigments were extracted with 0.01% acidified methanol, filtered, concentrated, centrifuged, decanted and scored to a defined volume for later evaluation.The anthocyanin spectra were identified by FTIR-ATR and Visible UV spectroscopy and the content of total anthocyanins (CAT) was evaluated by the differential pH method, total polyphenols (PFT) by the Folin-Ciocalteu method, found in the Visible and UV spectra. FTIR - ATR strong absorption signals at different values of vibration frequencies (cm-1) that correspond to functional groups of anthocyanins. The highest value in CAT corresponds to the extract of alaybili and the lowest to the condorusa with 108.12 and 56.07 (mg of cyanidin 3-glucoside / 100 g of fresh weight) respectively. Similarly, the highest value in PFT corresponds to alaybili and the lowest to condorusa with 627.13 and 342.24 (mg of gallic acid / 100 g of fresh weight) respectively. Therefore, it is concluded that the extracts of these fruits can be a source of functional foods as natural colorants in the food industry due to their high content of antioxidants. Keywords: Anthocyanins, Polyphenols, Antioxidants, Free Radicals, Flavonoids

Ultra-Wide Range Vibration Frequency Detection Sensors Based on Elastic Steel Triboelectric Nanogenerators for Intelligent Machinery Monitoring.

Vibration measurement and analysis play an important role in diagnosing mechanical faults, but existing vibration sensors are limited by issues such as dependence on external power sources and high costs. To overcome these challenges, the use of triboelectric nanogenerator (TENG)−based vibration sensors has recently attracted attention. These vibration sensors measure a small range of vibration frequencies and are not suitable for measuring high-frequency vibrations. Herein, a self-powered vibration sensor based on an elastic steel triboelectric nanogenerator (ES−TENG) is proposed. By optimizing the elastic steel sheet structure and combining time-frequency transformation and filtering processing methods, the measurement of medium- and high-frequency vibrations is achieved. These results demonstrate that the ES−TENG can perform vibration measurements in the range of 2–10,000 Hz, with a small average error (~0.42%) between the measured frequency and external vibration frequency values. Therefore, the ES−TENG can be used as a self-powered, highly-accurate vibration sensor for intelligent machinery monitoring.

Synthesis, characterizations of new Schiff base heterocyclic derivatives and their optoelectronic, computational studies with level II & III features of LFPs

Organic Schiff base compounds with luminous characteristics are receiving attention and increasing demand for the imaging of latent fingerprints (LFPs) at crime scenes. Sb1 and Sb2 novel Schiff base heterocyclic compounds were synthesized and confirmed by using analytical and spectroscopic methods. The existence of both donating and accepting groups influenced the appearance of absorption bands at longer wavelength and was recorded using UV-absorption and emission spectrum in solvent media. Compounds Sb1 and Sb2 emit at 576 nm and 646 nm in bathochromic shift respectively. The electrochemical properties were investigated using cyclic voltammetry. Quantum chemical parameters with vibrational frequency have been estimated in density functional theory (DFT), using TD-DFT/CAM (B3LYP) approach employing 6–311++ G (d, p) basis set in the ground state. Theoretical vibrational frequency values were specifically agreed to obtained experimental values. Furthermore, FMOs, MEPs, RDG analyses and Mulliken atomic charges have been calculated. In addition, LFPs images were developed by powder dusting approach on specified materials using synthetic compounds and visualized under Visible and UV light. The level II and III properties of LFPs on the substrate were observed under light-medium with no background interference, therefore these compounds are potential materials for electroluminescent, OLEDs and forensic science applications.

Vibro-induced weakening of interface friction between granular materials and textured surfaces: An experimental study with a modified direct shear apparatus

Underground structures below or adjacent to railway lines frequently suffer train-induced vibration. In order to better predict the structures’ performance under vibration, attention has been paid to investigating the behavior of soil-structure interfaces. Limited by the capabilities of current test apparatus, the soil-structure interface friction is mainly determined under static and quasi-static loading conditions. While the interface friction behavior under vibration has been rarely addressed, especially under high-frequency vibration. This study focuses on the frictional behavior of granular material-structure interfaces under coupled static and one-dimensional vibration loading, where influences of vibration intensity, frequency, normal stress, particle shape, surface roughness, moisture condition, and initial relative density are systematically analyzed. The results show that the vibration leads to friction weakening of the interface, showing as shear stress loss and shear displacement slip. For test conditions included in this study, the shear stress loss even reaches up to 50% of the shear stress prior to vibration. The friction weakening is found independent of the initial density when shearing at steady state. Critical values of water content and vibration frequency have been observed, where the shear strength loss and displacement slip reach their peaks.

Cellular Automaton Simulation of Dendrite Growth in Solidification Process of Cr17 Stainless Steel under Mechanical Vibration

Herein, a coupled model of temperature field and dendrite growth is built to examine the solidification microstructure of Cr17 stainless steel under vibration. The temperature field is calculated with ANSYS FLUENT software. In addition, considering solute diffusion and local curvature, a low grid anisotropic cellular automaton (CA) model is used to simulate the dendrite growth. To verify the major source of crystal nucleus in the melts, a mechanical model of dendrite fracture is built, and an investigation is conducted on the critical condition of grain dissociation. As indicated from the results, the dendrites are stripped and dissociated into the melt when the vibration frequency and amplitude values exceed the critical condition of dendrite fracture, the grains are dissociated more easily, and the more equiaxed grains are indicated in the melt with the increase in the vibration frequency. It is preliminarily demonstrated that vibration can facilitate the dendrites to break and be dissociated from the chilling generator surface. The simulation results comply with the experiment.

Effect of spin orbit coupling on antiperovskites: Sr3BO (B = Pb, Sn)

We present a comprehensive investigation examining the influence of spin–orbit coupling on structural, electronic, vibrational elastic, mechanical, and thermoelectric properties of cubic antiperovskites: Sr3PbO and Sr3SnO using first principles calculation. The incorporation of spin–orbit coupling has led to significant effect on physical properties by emergence of topological phase in both studied antiperovskites. The spin–orbit coupling has remarkable effect on the electronic properties by giving rise to separation of Valence band and Conduction band at Γ point and also by the origin of anti-crossing band feature with band gap of 27 meV and 16 meV at for Sr3PbO and Sr3SnO respectively along line adjoining Γ-X high symmetry points of Brillioun Zone. The inclusion of spin–orbit coupling brings about appreciable softening in the values of elastic, mechanical parameters and vibrational frequencies of phonon spectra. The incorporation of spin–orbit coupling has improved the thermoelectric performance by enhancing Seebeck coefficient and reducing thermal conductivity. The present simulation tends to simulate experimental research for constructive electronic, spintronics and thermoelectric applications.

Экспериментальное исследование колебаний капли воды в потоке воздуха при акустическом воздействии

The study focuses on the interaction between a gas flow and liquid drops and describes the proposed experimental setup in detail. First, we experimentally studied the vibrations of a drop with a diameter of 1.4 mm in the airflow with a speed of 3.1--10 m/s and by a high-speed Phantom camera with a frame rate of 2000 fps, we took a series of photographs of the drop in the airflow at regular intervals. Then, we calculated the spectra of free vibrations of the drop in a gas flow, as well as the vibrations affected by sound vibrations of the air with a frequency of 0--1000 Hz and a sound pressure level of 0--121 dB, and found the gas flow and acoustic radiation parameter regions, at which the drop vibrations amplitude is higher or lower. Next, by the Kelvin --- Helmholtz instability theory, we theoretically analyzed the airflow-acoustic radiation mutual influence on the liquid drop and considered the drop possible values of the Weber number under experimental conditions. Findings of the research show that the drop does not fragmentize in the airflow. Finally, we found the drop vibration frequency values in the airflow, at which the amplitude of oscillations is constant

Theoretical (6-311G(d,p)/ 3-21G) and Spectroscopic (13C/ 1H-NMR, FT-IR) Analyses pf 3-Propyl-4-[3-(2-Methylbenzoxy)-Benzylidenamino]-4,5-Dihydro-1h-1,2,4-Triazol-5-One Molecule

The molecule was studied with the method Density Functional Theory (DFT) using two different the basis sets (6-311G(d,p)/ 3-21G) in the Gaussian 09W program. First, the most stable three-dimensional shape of the molecule was determined with the GaussView5.0 program (Dennington et al., 2009). Based on the structure of this optimized molecule,"spectroscopic properties"(FT-IR, 13C/ 1H-NMR), the electronic properties (electron affinity (A), ionization potential (I), electronegativity (χ), chemical hardness and softness, electrophilic and nucleophilic index), HOMO-LUMO energies and ΔEg energy, the geometric properties (bond length and angle) ve the thermodynamic properties (thermal energy (E), thermal capacity (CV), entropy (S)) were calculated with DFT/ 6-311G(d,p) and 3-21G. In addition, the total energy of the molecule, mulliken atomic charge values, dipole moment, molecular electron potential (MEP), total density and contour surface maps were determined. The electrophilic and nucleophilic regions of the structure were confirmed. Theoretical calculations of 13C/ 1H-NMR isotropic shift values were performed in gas phase and solvent (DMSO) acording to GIAO method and regression analyzes were by compare with experimental values of computational data. R2 values were calculated and regression graphs were created. FT-IR (Infrared) vibration frequency values were calculated from the Veda4f program. The theoretical vibration frequency values were compared with the experimental IR values. Experimental data obtained from the literature.