Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.

1987 ◽  
Vol 105 ◽  
Author(s):  
Hisham Z. Massoud
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Dipole Moments ◽  
Silicon Substrates ◽  
Interface Dipole ◽  
Mos Devices ◽  
Flatband Voltage ◽  
The Difference ◽  
Definition Of ◽  
Mos Structures

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.

Experimental and computed dipole moments in donor–bridge–acceptor systems with p-phenylene and p-carboranediyl bridges

2009 ◽  
Vol 74 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Ladislav Drož ◽  
Mark A. Fox ◽  
Drahomír Hnyk ◽  
Paul J. Low ◽  
J. A. Hugh MacBride ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Electronic Effects ◽  
Electronic Interactions ◽  
Donor And Acceptor ◽  
Homo And Lumo ◽  
Pull Systems ◽  
The Difference ◽  
Experimental Values ◽  
2D And 3D

Dipole moments were measured for a series of substituted benzenes, biphenyls, terphenyls, C-monoaryl- and C,C′-diaryl-p-carboranes. For the donor–bridge–acceptor systems, Me2N–X–NO2, where X is 1,4-phenylene, biphenyl-4,4′-diyl, terphenyl and 1,4-C6H4-p-CB10H10C-1,4-C6H4, the measured interaction dipole moments are 1.36, 0.74, 0.51 and 0.00 D, respectively. The magnitude of the dipole moment reflects the ability of the bridge to transmit electronic effects between donor and acceptor groups. Thus, whilst the 1,4-phenylene bridges allow moderate electronic interactions between the remote groups, the p-carboranediyl unit is less efficient as a conduit for electronic effects. Averaged dipole moments computed at the DFT (B3LYP/6-31G*) level of theory from two distinct molecular conformers are in good agreement with the experimental values. Examination of the calculated electronic structures provides insight into the nature of the interactions between the donor and acceptor moieties through these 2D and 3D aromatic bridges. The most significant cooperative effect of the bridge on the dipole moment occurs in systems where there is some overlap between the HOMO and LUMO orbitals. This orbital overlap criterion may help to define the difference between “push-pull” systems in which electronic effects are mediated by the bridging moiety, and simpler systems in which the bridge acts as an electronically innocent spacer unit and through-space charge transfer/separation is dominant.

DIPOLE MOMENTS AND STRUCTURE OF MOLECULAR COMPOUNDS: PART I. ALIPHATIC AND AROMATIC AMINE PICRATES

1961 ◽  
Vol 39 (6) ◽  
pp. 1247-1252 ◽  
Author(s):  
R. Raman ◽  
Sundaresa Soundararajan
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Aromatic Amine ◽  
Dipole Moments ◽  
Ionic Character ◽  
Energy Of Interaction ◽  
The Moment ◽  
Vector Sum ◽  
Molecular Compounds ◽  
Activated Complex

Dipole moment measurements have been made for some aliphatic and aromatic amine picrates in dioxane solution. The fractional ionic character of these complexes in the ground state has been calculated from μN, the observed value of dipole moment; μ0, the vector sum of the moments of the components of the complex; μ1, the moment resulting from complete one-electron transfer; and known values of S, using the charge-transfer theory of Mulliken. For these complexes of the n + hσd type, the charge-transfer process lies in the direction of the symmetry axis N+O−, the picture corresponding to an energy of interaction U, versus charge-transfer co-ordinate (C) curve with a shallow minimum showing an inner complex corresponding to (C = 1), b = a2 or b2 > a2, and an activated complex (roughly between C = 0.3 to 0.5) corresponding to an intermediate.

Electric dipole moment of X2Π OH and OD in several vibrational states

1984 ◽  
Vol 62 (12) ◽  
pp. 1502-1507 ◽  
Author(s):  
K. I. Peterson ◽  
G. T. Fraser ◽  
W. Klemperer
Keyword(s):  
Dipole Moment ◽  
Electric Dipole ◽  
Vibrational State ◽  
Molecular Beam ◽  
Dipole Moments ◽  
Vibrational States ◽  
Electric Resonance ◽  
Resonance Technique ◽  
The Difference ◽  
Theoretical Results

Dipole moments are measured for OH (2Π) in the ν = 0, 1, and 2 vibrational states and for OD in the ν = 0 and 1 states using the molecular beam electric resonance technique. These are listed in the table below.[Formula: see text]A very accurate value of 0.00735(7) D is obtained for the difference in dipole moments between the ν = 0 and 1 vibrational states of OH. This is within 20% of the best theoretical results. The dependence on vibrational state is very nonlinear, which is also in agreement with theoretical results. Finally, the difference between the ν = 0 dipole moments of OH and OD is close to the expected value.

scholarly journals Solvent effect on the absorption and emission spectra of carbon dots: evaluation of ground and excited state dipole moment

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Parisa Mohammad-Jafarieh ◽  
Abolfazl Akbarzadeh ◽  
Rahman Salamat-Ahangari ◽  
Mohammad Pourhassan-Moghaddam ◽  
Kazem Jamshidi-Ghaleh
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Ground State ◽  
Carbon Dots ◽  
Dipole Moments ◽  
Emission Spectra ◽  
Aprotic Solvents ◽  
One Step ◽  
The Difference ◽  
Excited State Dipole Moment

Abstract Background Carbon dots (C-dots) are photoluminescent nanoparticles with less than 10 nm in size. Today, many studies are performed to exploit the photoluminescence (PL) property of carbon dots, and our focus in this study is to estimate the dipole moment of carbon dots. For reaching our aims, C-dots were synthesized and dissolved in the different solvents. Results Carbon dots with intense photoluminescence properties have been synthesized by a one-step hydrothermal method from a carbon bio-source. In this research, we report on the effect of aprotic solvents on absorption and fluorescence spectra and dipole moments of C-dots dispersed in a range of many aprotic solvents with various polarity and dielectric constant at room temperature. The change in the value of dipole moment was estimated by using the Stokes shifts. The difference between the dipole moment of the excited state and the ground state was shown using an extended form of Lippert equations by Kawski and co-workers. Conclusions The values found for μg = 1.077 D, and μe = 3.157 D, as well as the change in the dipole moments. The results showed that the dipole moment of the excited state is more than the ground state, indicating a high density and redistribution of electrons in the excited state. Finally, the quantum yield of C-dots in the eclectic aprotic solvents was communicated and discussed.

Dipole moment of the intramolecular hydrogen bond. 2-Nitrophenol and its derivatives

1983 ◽  
Vol 48 (3) ◽  
pp. 735-747 ◽  
Author(s):  
Otto Exner ◽  
Juraj Koudelka ◽  
Soňa Vašíčková
Keyword(s):  
Hydrogen Bond ◽  
Electron Transfer ◽  
Dipole Moment ◽  
Intramolecular Hydrogen Bond ◽  
Dipole Moments ◽  
Charge Redistribution ◽  
Experimental Dipole Moment ◽  
Mndo Calculations ◽  
The Difference ◽  
Intramolecular Hydrogen

Dipole moments of substituted 2-nitrophenols VIa-VIf and substituted 2-nitroanisoles VIIa to VIIf were measured in benzene and dioxan solutions. Infrared spectroscopy confirmed that nitrophenols VI exist either solvent and at different concentrations as non-associated molecules with an intramolecular hydrogen bond. Therefore, the difference between the experimental dipole moment and that calculated from group moments can be attributed to charge redistribution raised by the hydrogen bond. Only a minute part of it may be due to electron transfer through the ring (conjugation of the functional groups) as follows particularly from he comparison with nitroanisoles VII. Nevertheless, the charge transfer, expressed as the vector μH, amounts only 1.7 . 10-30 Cm (at an angle of 138° to the H-O bond), i.e. several times less than observed previously in compounds with more powerful hydrogen acceptors. CNDO/2 and MNDO calculations agree fairly with the gross dipole moments of the compounds investigated but are unable to predict μH, not even as far as its direction is concerned.

The Temporal Dipole Moment Of Solute Molecules Undergoing Charge Transfer

2004 ◽  
Vol 59 (7-8) ◽  
pp. 476-480 ◽  
Author(s):  
V. I. Tomin ◽  
A. Krzysztofowicz
Keyword(s):  
Correlation Function ◽  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Time Dependence ◽  
Electric Dipole ◽  
Polar Solvent ◽  
Dipole Moments ◽  
Experimental Methods ◽  
Geometrical Transformation

Important information about a geometrical transformation of solute molecules undergoing charge transfer in the excited state could be obtained from the knowledge of its dipole moment change in time, while experimental methods allow to obtain only stationary values of dipole moments for both the local excited and the charge transfer states. On the basis of the theory of solvatochromism the relation for a time dependence of dipole moment on the correlation function for instant spectra kinetics has been deduced. Time dependence of the electric dipole moment of dimethylaminobenzonithryle in a polar solvent is presented. The initial and the final values of the dipole moments are close to those obtained by means of stationary spectroscopy methods.

Memory Effects in the Collision-Induced Spectra of Noble Gases in Liquid Argon

1971 ◽  
Vol 49 (22) ◽  
pp. 2870-2873 ◽  
Author(s):  
U. Buontempo ◽  
S. Cunsolo ◽  
G. Jacucci
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Low Frequency ◽  
Far Infrared ◽  
Liquid Argon ◽  
Low Frequencies ◽  
Line Shapes ◽  
Induced Dipole ◽  
Rapid Fall ◽  
The Difference

We have measured the far infrared absorption spectra of dilute solutions of helium and neon in liquid argon arising from collision-induced electric dipole moments. The two spectra consist of broad bands similar in shape peaked at 70 cm−1 (Ne–A) and 120 cm−1 (He–A). They are characterized by a long high-frequency tail and a rapid fall at low frequency. The reduced line shapes are compared taking into account the difference in the duration of the collision-induced dipole moment. At high frequencies the two curves are similar to those observed in the gas phase. Their departure from the gaseous spectra at low frequencies is attributed to a negative correlation of the dipole moment induced in successive repulsive interactions.

The relationship between the rate–equilibrium coefficient α and transition state properties: a second-order Møller–Plesset perturbation study of SN2 reactions

1992 ◽  
Vol 70 (2) ◽  
pp. 450-455 ◽  
Author(s):  
Zheng Shi ◽  
Russell J. Boyd
Keyword(s):  
Charge Transfer ◽  
Transition State ◽  
Sn2 Reactions ◽  
Leaving Group ◽  
The Difference ◽  
Equilibrium Relationships ◽  
Moller Plesset ◽  
Definition Of ◽  
The Relationship ◽  
Abinitio Calculations

Abinitio calculations including electron correlation are used to study rate–equilibrium relationships in gas-phase SN2 reactions. The difference between the "intrinsic" α and "group" α is emphasized. In general, the "group" α cannot be used as a measure of the transition state structure. The relationships between the "intrinsic" α and other properties, such as reaction endothermicity, geometry change, and the charge transfer, are discussed. A geometry change parameter Rα, defined by analogy with the definition of the "intrinsic" α, is shown to be linearly related to the "intrinsic" α. The charge transfer at the transition state is related not only to energy changes but also to the electronegativities of the entering nucleophile and leaving group in the product and reactant, respectively, and to the electronic structures at the transition state. Thus, the charge transfer parameter Qα, unlike the "intrinsic" α and Rα, is affected by the electronegativities of the groups involved in the reaction. The systems studied are SN2 reactions of the type N− + CH3X → CH3N + X−, where X = H, NH2, OH, OOH, F, CCH, CN, NC, PH2, SH, and Cl when N = H, and where X = H, NH2, OH, F, CN, NC, PH2, SH, and Cl when N = F. Keywords: SN2 reactions, rate–equilibrium relationships, transition state properties.

Electric dipole moments and molar Kerr constants of Phenyl- and Diphenylpyridylmethanes

1973 ◽  
Vol 26 (10) ◽  
pp. 2077 ◽  
Author(s):  
KK Chiu ◽  
HH Huang
Keyword(s):  
Dipole Moment ◽  
Carbon Tetrachloride ◽  
Weak Interaction ◽  
Electric Dipole ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Electric Dipole Moments ◽  
Total Polarization ◽  
The Difference ◽  
Kerr Constants

The difference in total polarization (ΔP) or dipole moment (ΔP) of 2- benzyl-pyridine, 4-benzylpyridine, diphenyl-2-pyridylmethane, diphenyl- 3-pyridylmethane, or diphenyl-4-pyridylmethane in carbon tetrachloride relative to benzene solution provides evidence of weak interaction between these amines and the former solvent. The molar Kerr constants of the amines in the two solvents for 4-benzylpyridine and diphenyl-4- pyridylmethane are analysed to yield the preferred angles of orientation of the phenyl and 4-pyridyl rings in these two molecules.

Large Induced Interface Dipole Moments without Charge Transfer: Buckybowls on Metal Surfaces

2011 ◽  
Vol 2 (21) ◽  
pp. 2805-2809 ◽  
Author(s):  
Tobias Bauert ◽  
Laura Zoppi ◽  
Georg Koller ◽  
Alberto Garcia ◽  
Kim K. Baldridge ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Metal Surfaces ◽  
Dipole Moments ◽  
Interface Dipole
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