Experimental values of the rotational and vibrational constants and equilibrium structure of nitrogen trifluoride

2015 ◽  
Vol 312 ◽  
pp. 1-5 ◽  
Author(s):  
Hamid Najib
Keyword(s):  
Equilibrium Structure ◽  
Nitrogen Trifluoride ◽  
Experimental Values ◽  
Vibrational Constants

SPECTRES DE VIBRATION-ROTATION DE MOLECULES SIMPLES DIATOMIQUES OU POLYATOMIQUES AVEC LONG PARCOURS D'ABSORPTION: XII. LE SPECTRE DE C12O162 ENTRE 3500 ET 8000 CM−1 ET LES CONSTANTES MOLECULAIRES DE CETTE MOLECULE

1957 ◽  
Vol 35 (5) ◽  
pp. 608-648 ◽  
Author(s):  
Charles-P. Courtoy
Keyword(s):  
Near Infrared ◽  
Fermi Resonance ◽  
Absorption Bands ◽  
Rotational Constants ◽  
Vibrational Levels ◽  
Coriolis Perturbation ◽  
Vibration Rotation ◽  
Experimental Values ◽  
Vibrational Constants ◽  
Usual Formula

Numerous absorption bands of the molecule C12O162 have been obtained in the near infrared under high resolution with the help of a multiple path absorption cell. Of these bands, 27 have been analyzed, among them three Δ—Δ transitions.The usual formula for the vibrational levels has been extended to include cubic terms and the values of the vibrational constants are given. Similarly the rotational constants Bν have been expressed by a formula including quadratic terms and the constants in this formula are given. The values of B0 and Be obtained here are respectively 0.39021 ±.00004 and 0.39162 cm−1.The l-type doubling constant qν of the Π states (apart from effects of Fermi resonance) can be represented by[Formula: see text].The perturbation term of the Fermi resonance is given by the expression[Formula: see text],where the quantum number l does not enter the first factor. The introduction of this expression allows one to represent all the vibrational levels as well as the rotational constants of each level and the constant q of the Π states with excellent precision.The value of D0 is found to be 13.5 × 10−8 cm−1. The effect of the Fermi resonance and of the perturbation between levels (ν1, ν2, l, ν3) and (ν1, ν2, l ± 2, ν3) on the constants D is discussed. The experimental values for these constants agree in a very satisfactory way with those calculated by Amat, Goldsmith, and Nielsen as do the constants μ of l-type doubling of the Π states.Finally the effect of Coriolis perturbation between the levels 3200 and (0511)c is demonstrated.

Ab initio Studies on Hydrazines: 2H-1,2,3-Triazol-2-amine With Special Reference to Its Equilibrium Structure and Vibrational Spectrum

1989 ◽  
Vol 42 (3) ◽  
pp. 433 ◽  
Author(s):  
NV Riggs
Keyword(s):  
Hydrogen Bonding ◽  
Vibrational Energy ◽  
Zero Point ◽  
Equilibrium Structure ◽  
Basis Sets ◽  
Transition Structure ◽  
Hydrogen Atoms ◽  
Ring Nitrogen ◽  
Experimental Values ◽  
Double Hydrogen

The geometries of four stationary structures of 2H-1,2,3-triazol-2-amine have been optimized with the 3-21G and 3-21G(N*) basis sets. The lowest-energy and only equilibrium structure predicted by these calculations is the 'perpendicular' Cs form (3), whereas infrared studies on benzo-annelated analogues had suggested it might be the 'parallel' Cs form (2) stabilized by 'double hydrogen-bonding' of the amino-hydrogen atoms to the flanking ring-nitrogen atoms. The latter form (2) is here characterized as the transition structure for rotation about the N-NH2 bond and, after zero-point vibrational-energy corrections, is calculated to lie 8.7 kJ mol-1 above the equilibrium structure (3) at HF/3-21G(N*) level or only 3.8 kJ mol-1 at MP4/6-31G** level. This very low barrier to internal rotation (cf. 26.5 kJ mol-1 for the analogous 1H-pyrrol-1-amine) may be due to double hydrogen-bonding of the kind suggested by the experimental study mentioned above. The transition structure for inversion at the NH2 centre is, as for 1H-pyrrol-1-amine, the perpendicular C2v structure (5), the barrier being 25.8 kJ mol-1 (cf. 24.5 kJ mol-1 for 1H-pyrrol-1-amine), and the planar C2v structure (4) is a second-order saddle point lying 41.7 kJ mol-1 above the equilibrium structure (3). Calculated NH-stretching frequencies, their separation, and relative intensities as compared with experimental values for benzo-annelated analogues offer broad support for the assignments above based on relative energies.

scholarly journals Rovibrational Interaction and Vibrational Constants of the Symmetric Top Molecule14NF3

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Hamid Najib
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
High Resolution ◽  
Ab Initio ◽  
Millimeter Wave ◽  
Fourier Transform Infrared ◽  
Interaction Parameters ◽  
Centimeter Wave ◽  
Experimental Values ◽  
Vibrational Constants

Several accurate experimental values of the and rotation-vibration interaction parameters and , , and vibrational constants have been extracted from the most recent high-resolution Fourier transform infrared, millimeter wave, and centimeter wave investigations in the spectra of the oblate symmetric top molecule14NF3. The band-centres used are those of the four fundamental, the overtones, the combination, and hot bands identified in the region between 400 cm−1and 2000 cm−1. Comparison of our constants with the ones measured previously, by infrared spectroscopy at low resolution, reveals orders of magnitude higher accuracy of the new values. The agreement between our values and those determined byab initiocalculations employing the TZ2Pf basis is excellent.

Vesicles as an equilibrium structure of a simple surfactant-water system

1994 ◽  
Vol 4 (9) ◽  
pp. 1585-1604 ◽  
Author(s):  
L. Cantù ◽  
M. Corti ◽  
E. Del Favero ◽  
A. Raudino
Keyword(s):  
Water System ◽  
Equilibrium Structure

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

Ability of Naphthoquinondiazide Photoresists to Exothermic Decomposition

2020 ◽  
pp. 90-96
Author(s):  
A.N. Shushpanov ◽  
◽  
A.Ya. Vasin ◽  
V.M. Raykova ◽  
G.G. Gadzhiev ◽  
...  
Keyword(s):  
Convective Heat Exchange ◽  
Inert Atmosphere ◽  
Necessary Condition ◽  
Critical Temperatures ◽  
Good Convergence ◽  
Measuring Devices ◽  
Explosive Transformation ◽  
Exothermic Decomposition ◽  
Experimental Approaches ◽  
Experimental Values

The article considers two intermediate products of positive photoresists (1,2-naphthoquinonediazide-(2)-5-sulfonic acid of monosodium salt — Dye M and 1,2-naphthoquinonediazide-(2)-5-sulfochloride — Dye N2) from the standpoint of the tendency to explosive transformation. The experimental values of flash points determined on the OTP setup were 130 °C for Dye M and 95 °C for Dye N2. These values are close to the temperatures of the beginning of intensive exothermic decomposition (132 and 111 °C, respectively) obtained by thermogravimetric analysis. In addition, this analysis showed the presence of exothermic peaks in the studied samples both in the air and in an inert atmosphere of helium, which is a necessary condition for the manifestation of a tendency to explosive transformation. To confirm the possibility of explosive transformation, the flash points of substances were also determined by the calculation method according to the formula, which is a consequence of the problem of thermal explosion during convective heat exchange with the environment, and gave a result close to the experimental one (the values were 138 and 105 °C, respectively). For this calculation the following was used: the kinetic parameters determined by the Kissinger method, the values of the density of substances determined on an automatic pycnometer, as well as the values of the heat of explosive transformation obtained with the help of the Real computer thermodynamic program. The research results confirming the tendency of the investigated compounds to explosive transformation, as well as the critical temperatures, exceeding which is unacceptable, were transferred to the production of FGUP GNTs NIOPIK to create a safe technological process, safe storage and transportation conditions. Considering the accuracy of the measuring devices, the process temperature should not exceed 125 °C for Dye M and 90 °C for Dye N2. The conducted studies and calculations show that the computational and experimental approaches have good convergence, give values in a close temperature range, and increase the reliability of the obtained results.

Automated Assessment of Binding Affinity via Alchemical Free Energy Calculations

2020 ◽  
Author(s):  
Maximilian Kuhn ◽  
Stuart Firth-Clark ◽  
Paolo Tosco ◽  
Antonia S. J. S. Mey ◽  
Mark Mackey ◽  
...  
Keyword(s):  
Free Energy ◽  
Protein Structures ◽  
Free Energy Calculations ◽  
Distinct Advantage ◽  
Binding Affinities ◽  
Structure Based Drug Design ◽  
Energy Calculations ◽  
Kendall’S Τ ◽  
Experimental Values ◽  
Better Than

Free energy calculations have seen increased usage in structure-based drug design. Despite the rising interest, automation of the complex calculations and subsequent analysis of their results are still hampered by the restricted choice of available tools. In this work, an application for automated setup and processing of free energy calculations is presented. Several sanity checks for assessing the reliability of the calculations were implemented, constituting a distinct advantage over existing open-source tools. The underlying workflow is built on top of the software Sire, SOMD, BioSimSpace and OpenMM and uses the AMBER14SB and GAFF2.1 force fields. It was validated on two datasets originally composed by Schrödinger, consisting of 14 protein structures and 220 ligands. Predicted binding affinities were in good agreement with experimental values. For the larger dataset the average correlation coefficient Rp was 0.70 ± 0.05 and average Kendall’s τ was 0.53 ± 0.05 which is broadly comparable to or better than previously reported results using other methods. <br>

Xe···OCS: Relatively Straightforward?

2020 ◽  
Author(s):  
Peter Kraus ◽  
Daniel A. Obenchain ◽  
Sven Herbers ◽  
Dennis Wachsmuth ◽  
Irmgard Frank ◽  
...  
Keyword(s):  
Relativistic Effects ◽  
Equilibrium Structure ◽  
Microwave Spectroscopy ◽  
Mass Dependent

<div>The Xe···OCS complex is studied using microwave spectroscopy. Nine isotopologues are measured, and a mass-dependent rm(2) structure is presented. The experiments are supported with a wide array of calculations, including CCSD(T), SAPT, as well as double-hybrid DFT. Trends in the structures of six Rg···OCS complexes (He, Ne, Ar, Kr, Xe, and Hg) are investigated, with particular attention to the deformation of the OCS monomer and relativistic effects. The experimental near-equilibrium structure of Xe···OCS can be predicted to within 11 milliangstrom in the Xe···C distance by correlated wavefunction theory.<br></div>

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