THEORETICAL STUDY ON INTERNAL ROTATION OF NITROSOUREAS AND TOXICOLOGICAL ANALYSIS

2007 ◽  
Vol 06 (02) ◽  
pp. 245-253 ◽  
Author(s):  
YA SONG CUI ◽  
LI JIAO ZHAO ◽  
YONG DONG LIU ◽  
RU GANG ZHONG
Keyword(s):  
Transition State ◽  
Internal Rotation ◽  
Ground State ◽  
Energy Barrier ◽  
Theoretical Study ◽  
Rotational Energy ◽  
Carcinogenic Potency ◽  
Toxicological Analysis ◽  
Ground State Structures ◽  
The Relationship

A theoretical study has been carried out for internal rotation of nitrosoureas at the B3LYP/6-311G* level of theory. For each nitrosourea compound, two ground state structures have been found and the E isomer is predicted to be more stable than the Z isomer. Two transition state conformations for the isomerization have also been obtained and the calculated results show that the isomerization through TS1 is easier than that through TS2. The relationship between energy barrier and toxicity has also been investigated. It is concluded that the carcinogenic potency increases along with the decrease of rotational energy barrier.

scholarly journals Determination and Study the Energy Characteristics of Vibrational-Rotational Levels and Spectral Lines of GaF, GaCl, GaBr and GaI for Ground State

2015 ◽  
Vol 50 ◽  
pp. 96-112
Author(s):  
Adil Nameh Ayaash
Keyword(s):  
Quantum Number ◽  
Computer Model ◽  
Ground State ◽  
Theoretical Study ◽  
Rotational Quantum Number ◽  
Spectral Lines ◽  
Vibrational Quantum Number ◽  
Energy Characteristics ◽  
Number Increase ◽  
The Relationship

A theoretical study of four gallium monohalides molecules (GaF, GaCl, GaBr and GaI) of ground state 1∑+ by using computer model is presented to study the energy characteristics of vibrational-rotational levels as a function of the vibrational and rotational quantum number , respectively. The calculations has been performed to examine the vibrational-rotational characteristics of some gallium halides molecules. These calculations appeared that all energies (Gv, Ev,J, and Fv,J) increase with increasing vibrational and rotational quantum number and by increasing the vibrational quantum number, and by increasing the vibrational quantum number, the vibrational constant will decrease. Also theoretical study of spectra of these molecules for ground state 1∑+ has been carried out. The values of spectral lines R(J) and P(J) were calculated and the relationship between the spectral lines and the rotational quantum number was established. The results appeared the spectra line values R(J) increases when the values of rotational quantum number decrease but the spectra line values P(J) decrease when the values of rotational quantum number increase, also the spectra line values P(J) decrease when the values of (m) increase, while the values of R(J) increase at first, then decrease showing Fortrar parabola.

Ab initio studies on amides: triformamide

1981 ◽  
Vol 34 (1) ◽  
pp. 7
Author(s):  
L Radom ◽  
NV Riggs
Keyword(s):  
Double Bond ◽  
Transition State ◽  
Ab Initio ◽  
Internal Rotation ◽  
Direct Observation ◽  
Ground State ◽  
Basis Set ◽  
Model Transition ◽  
Bond Character ◽  
Complete Optimization

Complete optimization with the STO-3G basis set of the geometries of the planar ground-state conformers of the (unknown) triformamide molecule predicts that the E,E,E conformer will be more stable than the E,Z,Z conformer by 12.6 kJ mol-1 (or 42.3 kJ mol-1 by energy evaluations with the 4-31G basis set). These differences make direct observation of the E,Z,Z-conformer unlikely. Corresponding optimization of a model transition state for the conversion of the E,Z,Z into the E,E,E conformer suggests that the barrier to internal rotation is low with a calculated height of 33 kJ mol-1 (24 kJ mol-1 when evaluated with the 4-31G basis set). Successive formyl substitution in ammonia, represented by the series of molecules formamide, diformamide (formimide) and triformamide, leads to decreasing double-bond character in the N-C bonds as reflected in increasing N-C bond lengths, decreasing Mulliken π-overlap populations and decreasing barriers to rotation. Extension of the results for these three molecules suggests that the (known) triacetamide molecule has a non-planar E,E,E-type structure as is consistent with the observation of a single signal in its 1H n.m.r. spectrum.

scholarly journals Modelling isolated hydrogen impurity in Lu2O3 with muonium spectroscopy

2020 ◽  
Vol 233 ◽  
pp. 04001
Author(s):  
Rui C. Vilão ◽  
Ricardo B.L. Vieira ◽  
Helena V. Alberto ◽  
João M. Gil ◽  
Alois Weidinger ◽  
...  
Keyword(s):  
Excited State ◽  
Transition State ◽  
Ground State ◽  
Energy Barrier ◽  
Reaction Process ◽  
Intermediate Step ◽  
Special Role ◽  
Hydrogen Impurity ◽  
Rearrangement Processes

We identified in this experiment two muon configurations in Lu2O3, the oxygen-bound (O-Mu+) ground state and a metastable (energy barrier 0.7(3) eV) atom-like excited state. These configurations are partially not formed immediately after implantation but somewhat delayed due to the requirement of a lattice rearrangement around the muon. These rearrangement processes occur on a timescale of ns to µs and are thus observable in µSR experiments. A special role plays a fairly long-lived (ns to µs) transition state as an intermediate step in the reaction process.

scholarly journals Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

2013 ◽  
Vol 88 (18) ◽  
Author(s):  
Guoying Gao ◽  
Roald Hoffmann ◽  
N. W. Ashcroft ◽  
Hanyu Liu ◽  
Aitor Bergara ◽  
...  
Keyword(s):  
Ground State ◽  
Theoretical Study ◽  
Structures And Properties ◽  
Ground State Structures

POLARON IN A QUANTUM DOT UNDER AN ELECTRIC FIELD

2007 ◽  
Vol 21 (24) ◽  
pp. 1635-1642
Author(s):  
MIAN LIU ◽  
WENDONG MA ◽  
ZIJUN LI
Keyword(s):  
Quantum Dot ◽  
Electric Field ◽  
Field Intensity ◽  
Ground State Energy ◽  
Ground State ◽  
Electric Field Intensity ◽  
State Energy ◽  
Theoretical Study ◽  
The Moment ◽  
Transformation Methods

We conducted a theoretical study on the properties of a polaron with electron-LO phonon strong-coupling in a cylindrical quantum dot under an electric field using linear combination operator and unitary transformation methods. The changing relations between the ground state energy of the polaron in the quantum dot and the electric field intensity, restricted intensity, and cylindrical height were derived. The numerical results show that the polar of the quantum dot is enlarged with increasing restricted intensity and decreasing cylindrical height, and with cylindrical height at 0 ~ 5 nm , the polar of the quantum dot is strongest. The ground state energy decreases with increasing electric field intensity, and at the moment of just adding electric field, quantum polarization is strongest.

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