scholarly journals The Impacts of Various Media on the Electronic Spectrum of Aniline Violet

2021 ◽  
Vol 2 (24) ◽  
pp. 28-55
Author(s):  
Sokaina Hemdan ◽  
◽  
Asma Al Jebaly ◽  
Fatma Ali
Keyword(s):  
Hydrogen Bonding ◽  
Absorption Band ◽  
Dissociation Constant ◽  
Relative Permittivity ◽  
Spectral Characteristics ◽  
Solvent Polarity ◽  
Isosbestic Point ◽  
Solvent Interactions ◽  
Solvent Parameters ◽  
The Impact

The solvent impact can be decided by Solvent polarity scales, a solvatochromic parameter that has a distinctive position of UV-Visible absorption band within the extend between 250 and 700 nm. The spectral characteristics of Aniline Violet in several solvents at room temperature were analyzed which is that the point of considering the impact of solvents on the absorption spectra of this cationic dye in organic solvent of distinctive characters. The solvent impacts on the wavenumber of the absorption band maxima (max) were talked about utilizing the taking after solvent parameters, refractive index, n, relative permittivity, ε and therefore the empirical solvent polarity ET (30), (*,  and ) and (SA, SB, SP and SPd). The solute–solvent interactions were decided on the premise of multilinear solvation energy relationships concept. The fitting coefficients gotten from this analysis allowed us to estimate the contribution of each type of interactions to the total spectral shifts in solution. The set up dependences between max and the solvent parameters emphasize that the visible band of the examined molecule is influenced by both non-specific and specific solute–solvent interactions. The results appeared the solvent polarizability has major impact on the spectral shift instead of hydrogen bonding accepting ability. Catalan strategy show higher acceptable correlation than Kamlet-Taft methodology and Katritzky methodology. The dissociation constant pKa and the isosbestic point of the explored compound were shown the presence of the individual predominate ionic species was assigned by constructing distribution charts at diverse pH ranges. The results showed that the relative permittivity constant, ε, is important factor affecting on the magnitude of the dissociation constant beside the hydrogen bonding of the solvent.

scholarly journals Theoretical Investigation of the Modeling of Indole –dichlormethane Hydrogen Bonding in Different Solvents

2021 ◽  
Author(s):  
Jamelah S. Al-Otaibi ◽  
Y.Sheena Mary ◽  
Y.Shyma Mary
Keyword(s):  
Hydrogen Bonding ◽  
Theoretical Investigation ◽  
Molecular Interactions ◽  
Vibrational Spectra ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Spectral Characteristics ◽  
Chemical Calculation ◽  
Peak Location ◽  
The Impact

Abstract Theoretical vibrational spectra of indole (IND) and its binary combination with dichloromethane (DC) in various solvents were computed to track the impact of molecular interactions on drug spectral characteristics. When transitioning from plain drug to complexes, 3561.26 cm− 1 mode of the IND displays a substantial shift in peak location. The 3561.26 band shows (~ 15.58) red shift upon dilution. The geometry of drug and IND-DC complex in various solvents was calculated using quantum chemical calculation utilizing DFT.

A contribution to evaluation of influence of medium in electronic and infrared spectroscopy

1982 ◽  
Vol 47 (4) ◽  
pp. 1060-1068 ◽  
Author(s):  
Vojtěch Bekárek ◽  
Jan Juřina
Keyword(s):  
Refractive Index ◽  
Infrared Spectroscopy ◽  
Correlation Coefficient ◽  
Solvent Effects ◽  
Electronic Spectra ◽  
Relative Permittivity ◽  
Solvent Parameters

Dependence of ET(30) of solvent parameters on relative permittivity (ε) and refractive index (n) of solvent has been found for forty solvents in the form ET(30)=29.87 + 72.03 (ε - 1/(2ε + 1)-29.16(ε - 1) (n 2 - 1)/(2ε + 1) (2n2 + 1), the correlation coefficient being 0.958. Relation has been discussed between ET(30) and π solvent parameters and significance of the term (ε - 1). (n2 - 1)/(2ε + 1) (2n2 + 1) has been tested for evaluation of solvent effects in electronic spectra.>

scholarly journals pH-controlled hydrogen-bonding (Short Communication)

1974 ◽  
Vol 143 (3) ◽  
pp. 775-777 ◽  
Author(s):  
John L. Wood
Keyword(s):  
Hydrogen Bonding ◽  
Dissociation Constant ◽  
Small Proportion ◽  
Association Constant ◽  
Short Communication ◽  
Dibasic Acid ◽  
Ph Dependence ◽  
Ph Values ◽  
Conjugate Acid ◽  
Total Base

The pH-dependence of the degree of hydrogen-bonding between a base and its conjugate acid is considered. When only a small proportion of the total base is complexed, the amount complexed is proportional to (1+coshp)−1 where p=2.303 (pKa–pH), pKa being the dissociation constant of the conjugate acid. This represents sharp pH-dependence. As the proportion complexed increases, the curve broadens, eventually becoming flat-topped, with more than half the base complexed over the range of pH values pKa±logKC, approximately. (K is the complex association constant and C is the formal base concentration, including all forms.) There are similarities to the extent of mono-protonation of a dibasic acid.

Solvent, coordination and hydrogen-bond effects on the chromic luminescence of the cationic complex [(phen)(H2O)Re(CO)3]+

2016 ◽  
Vol 40 (7) ◽  
pp. 6451-6459 ◽  
Author(s):  
Pablo Mella ◽  
Karina Cabezas ◽  
Carla Cerda ◽  
Marjorie Cepeda-Plaza ◽  
German Günther ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solvent Polarity ◽  
Cationic Complex ◽  
Unusual Behavior ◽  
Luminescence Emission

The unusual behavior of the solution luminescence emission of [(phen)(H2O)Re(CO)3]+(CF3SO3)− depends on the solvent polarity, and coordinating and hydrogen bonding ability.

scholarly journals Small Changes: Using Assessment to Direct Instructional Practices in Large-Enrollment Biochemistry Courses

2017 ◽  
Vol 16 (1) ◽  
pp. ar7 ◽  
Author(s):  
Xiaoying Xu ◽  
Jennifer E. Lewis ◽  
Jennifer Loertscher ◽  
Vicky Minderhout ◽  
Heather L. Tienson
Keyword(s):  
Hydrogen Bonding ◽  
Student Performance ◽  
Bond Energy ◽  
Multiple Choice ◽  
Instructional Interventions ◽  
Student Responses ◽  
Large Classes ◽  
Instructional Effect ◽  
Large Enrollment ◽  
The Impact

Multiple-choice assessments provide a straightforward way for instructors of large classes to collect data related to student understanding of key concepts at the beginning and end of a course. By tracking student performance over time, instructors receive formative feedback about their teaching and can assess the impact of instructional changes. The evidence of instructional effectiveness can in turn inform future instruction, and vice versa. In this study, we analyzed student responses on an optimized pretest and posttest administered during four different quarters in a large-enrollment biochemistry course. Student performance and the effect of instructional interventions related to three fundamental concepts—hydrogen bonding, bond energy, and pKa—were analyzed. After instructional interventions, a larger proportion of students demonstrated knowledge of these concepts compared with data collected before instructional interventions. Student responses trended from inconsistent to consistent and from incorrect to correct. The instructional effect was particularly remarkable for the later three quarters related to hydrogen bonding and bond energy. This study supports the use of multiple-choice instruments to assess the effectiveness of instructional interventions, especially in large classes, by providing instructors with quick and reliable feedback on student knowledge of each specific fundamental concept.

scholarly journals Turbulence coherence and its impact on wind-farm power fluctuations

2018 ◽  
Vol 855 ◽  
pp. 1116-1129 ◽  
Author(s):  
Nicolas Tobin ◽  
Leonardo P. Chamorro
Keyword(s):  
Power Spectrum ◽  
Atmospheric Turbulence ◽  
Turbulent Diffusion ◽  
Wind Farm ◽  
Spectral Characteristics ◽  
Wind Farms ◽  
High Frequencies ◽  
Power Fluctuations ◽  
The Impact ◽  
Coherence Spectrum

Using a physics-based approach, we infer the impact of the coherence of atmospheric turbulence on the power fluctuations of wind farms. Application of the random-sweeping hypothesis reveals correlations characterized by advection and turbulent diffusion of coherent motions. Those contribute to local peaks and troughs in the power spectrum of the combined units at frequencies corresponding to the advection time between turbines, which diminish in magnitude at high frequencies. Experimental inspection supports the results from the random-sweeping hypothesis in predicting spectral characteristics, although the magnitude of the coherence spectrum appears to be over-predicted. This deviation is attributed to the presence of turbine wakes, and appears to be a function of the turbulence approaching the first turbine in a pair.

scholarly journals Reflection of sound pulses from an inhomogeneous bubble medium

2021 ◽  
Vol 2057 (1) ◽  
pp. 012032
Author(s):  
I A Ogorodnikov
Keyword(s):  
Absorption Band ◽  
Emission Spectrum ◽  
Initial Phase ◽  
Volume Concentration ◽  
Transition Radiation ◽  
Spectral Characteristics ◽  
Bubble Medium ◽  
Boundary Zone ◽  
Initial Stage ◽  
Sound Pulses

Abstract The effect of changes in the volume concentration of bubbles in the boundary zone of the bubble medium on the nature of reflection and radiation of the excited bubble medium is studied. The spectral characteristics of the radiation of a bubble medium are obtained at the initial stage of transition radiation and at large times when the radiation is stationary. It is shown that in the initial phase the emission spectrum is broadband and is located in the absorption band of the bubble medium, and at large times the emission spectrum is located outside this band.

scholarly journals Экспериментальное и теоретическое исследование осциллятора с соударениями

2020 ◽  
Vol 90 (10) ◽  
pp. 1672
Author(s):  
В.В. Нарожнов
Keyword(s):  
Theoretical Model ◽  
Equations Of Motion ◽  
Spectral Characteristics ◽  
Contact Theory ◽  
Hertz Contact ◽  
Mechanical Oscillator ◽  
Impact Oscillator ◽  
Fourier Filtering ◽  
Nonlinear Mechanical ◽  
The Impact

The results of a study of a nonlinear mechanical oscillator with elastic impacts are presented. The experiment was carried out using an electromechanical impact oscillator. The theoretical model is based on the equations of motion, taking into account the elastic force, which is calculated under the Hertz contact theory. It is shown that bifurcations and attractors of the “stable focus” and “limit cycle” types can occur for the impact oscillator. Fourier filtering was used to analyze the spectral characteristics of the signals.

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