scholarly journals Quantum dynamics of the ππ*/nπ* decay of the epigenetic nucleobase 1,5-dimethyl-cytosine in the gas phase

2020 ◽  
Vol 22 (45) ◽  
pp. 26525-26535
Author(s):  
Martha Yaghoubi Jouybari ◽  
Yanli Liu ◽  
Roberto Improta ◽  
Fabrizio Santoro
Keyword(s):  
Gas Phase ◽  
Quantum Dynamics ◽  
Vibrational Modes

A partial ultrafast ππ* → nπ* transfer is predicted. Many vibrational modes are activated, but oscillations of bonds and angles are quickly damped.

Exploring the Mechanism of Ultrafast Intersystem Crossing in Rhenium(I) Carbonyl Bipyridine Halide Complexes: Key Vibrational Modes and Spin–Vibronic Quantum Dynamics

2016 ◽  
Vol 12 (5) ◽  
pp. 2335-2345 ◽  
Author(s):  
Yu Harabuchi ◽  
Julien Eng ◽  
Etienne Gindensperger ◽  
Tetsuya Taketsugu ◽  
Satoshi Maeda ◽  
...  
Keyword(s):  
Quantum Dynamics ◽  
Intersystem Crossing ◽  
Vibrational Modes ◽  
Halide Complexes

STRUCTURAL, ELECTRONIC AND QSAR PROPERTIES OF THE CYFLUTHRIN MOLECULE: A THEORETICAL AM1 AND PM3 TREATMENT

2006 ◽  
Vol 17 (10) ◽  
pp. 1391-1402 ◽  
Author(s):  
EMİNE DENİZ ÇALIŞIR ◽  
ŞAKİR ERKOÇ
Keyword(s):  
Energy Level ◽  
Gas Phase ◽  
Ground State ◽  
Heat Of Formation ◽  
Tobacco Budworm ◽  
Vibrational Modes ◽  
Lumo Energy ◽  
Deciduous Fruit ◽  
Semi Empirical ◽  
Homo Energy Level

Cyfluthrin is a synthetic cyano-containing pyrethroid insecticide that has both contact and stomach poison action. It is a nonsystemic chemical used to control cutworms, ants, silverfish, cockroaches, mosquitoes, tobacco budworm and many others. Its primary agricultural uses have been for control of chewing and sucking insects on crops such as cotton, turf, ornamentals, hops, cereal, corn, deciduous fruit, peanuts, potatoes, and other vegetables. Cyfluthrin is also used in public health situations and for structural pest control. The structural, vibrational, electronic and QSAR properties of the cyfluthrin molecule in gas phase have been investigated theoretically by performing molecular mechanics method by using MM+ force field, and semi-empirical molecular orbital AM1 and PM3 calculations. The geometry of the molecule has been optimized, infrared spectrum (vibrational modes and intensities) and the electronic properties of the molecule have been calculated in its ground state. According to PM3 calculation, heat of formation of cyfluthrin molecule is about -48.58 kcal/mol (exothermic), which shows that this molecule thermodynamically be stable. The HOMO energy level for this molecule is found to be -9.701 eV and the LUMO energy level is -0.660 eV giving rise to a gap of 9.041 eV, which also indicates that cyfluthrin is thermodynamically stable.

scholarly journals Unknown Knowns: Case Studies in Uncertainties in the Computation of Thermochemical Parameters

2020 ◽  
Author(s):  
John Simmie
Keyword(s):  
Heat Capacity ◽  
Gas Phase ◽  
Basis Set ◽  
Statistical Thermodynamic ◽  
Vibrational Modes ◽  
Heavy Atoms ◽  
New Methods ◽  
Formation Enthalpies ◽  
Thermochemical Parameters

<div>Both the computation of, and the uncertainties associated, with gas-phase molar formation enthalpies are now quite well established for systems comprised of tens of ‘heavy’ atoms chosen from the commonest elements. The same cannot be said for derived thermochemical quantities such as entropy, heat capacity and an enthalpy function. Whilst the application of well known statistical thermodynamic relations is mostly understood, the determination of the uncertainty with which such values can be obtained has been little studied — apart, that is, for a general protocol devised by Goldsmith et al. [J. Phys. Chem. A, 2012, 116, 9033–9057]. Specific examples from that work are explored here and it is shown that their estimates are overly pessimistic. It is also evident that for some species the calculated thermochemical parameters show very little variation with either the level of theory, or basis set, or treatment of vibrational modes — this renders the inclusion of such species in databases designed to validate new methods of limited value.<br></div>

Etude à basse température dans l'infrarouge proche du dimère (NO)2

1984 ◽  
Vol 62 (4) ◽  
pp. 322-329 ◽  
Author(s):  
V. Menoux ◽  
R. Le Doucen ◽  
C. Haeusler ◽  
J. C. Deroche
Keyword(s):  
Excited State ◽  
Gas Phase ◽  
Ground State ◽  
Near Infrared ◽  
Heat Of Formation ◽  
Wave Number ◽  
Vibrational Modes ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Absorption Intensity

The spectrum of the dimer (NO)2 in the gas phase has been studied in the near infrared at temperatures between 118 and 138 K. More specifically, the measure of absorption intensity of the ν4 and ν1 + ν4 bands has yielded the heat of formation of the dimer, −2.25 kcal/mol at 128 K, and revealed the influence of the low vibrational modes on this measure. The observation of the ν4 – ν6, difference band has yielded the wave number value of the ν6, fundamental band, forbidden in the infrared. The rotational constants of the vibrationally excited state were found to be larger than the ground state rotational constants, this result being very unusual.

Multistate coupled quantum dynamics of photoexcited cytosine in gas-phase: Nonadiabatic absorption spectrum and ultrafast internal conversions

2018 ◽  
Vol 515 ◽  
pp. 452-463 ◽  
Author(s):  
Yanli Liu ◽  
Lara Martínez-Fernández ◽  
Javier Cerezo ◽  
Giacomo Prampolini ◽  
Roberto Improta ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Gas Phase ◽  
Quantum Dynamics

scholarly journals The role of vibronic coupling in the electronic spectroscopy of maleimide: a multi-mode and multi-state quantum dynamics study

2020 ◽  
Vol 22 (43) ◽  
pp. 25272-25283
Author(s):  
Andreas Lehr ◽  
Sandra Gómez ◽  
Michael A. Parkes ◽  
Graham A. Worth
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Excited States ◽  
Electronic Absorption ◽  
Quantum Dynamics ◽  
Electronic Spectroscopy ◽  
Vibrational Modes ◽  
Model Hamiltonian ◽  
Multi Mode

The first two excitation bands below 7 eV in the electronic absorption spectrum of maleimide are investigated using a model Hamiltonian including four low-lying singlet excited states within the manifold of 24 vibrational modes.

Low-energy vibrational spectra of flexible diphenyl molecules: biphenyl, diphenylmethane, bibenzyl and 2-, 3- and 4-phenyltoluene

2014 ◽  
Vol 16 (40) ◽  
pp. 22062-22072 ◽  
Author(s):  
M. A. Martin-Drumel ◽  
O. Pirali ◽  
C. Falvo ◽  
P. Parneix ◽  
A. Gamboa ◽  
...  
Keyword(s):  
Gas Phase ◽  
Vibrational Spectra ◽  
Accurate Determination ◽  
Low Frequency ◽  
Low Energy ◽  
Vibrational Modes ◽  
Phase Spectra

Gas phase spectra of six bi-phenyl molecules are reported allowing an accurate determination of their active low-frequency vibrational modes.

Quantum Dynamics of Gas-Phase SN2 Reactions

ChemPhysChem ◽  
2004 ◽  
Vol 5 (5) ◽  
pp. 600-617 ◽  
Author(s):  
Stefan Schmatz
Keyword(s):  
Gas Phase ◽  
Quantum Dynamics ◽  
Sn2 Reactions
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