DYNAMICS OF THE N(2D)+H2 REACTION ON THE $\tilde{X}^2 A^{\prime\prime}$ SURFACE, PROPAGATING REAL WAVE PACKETS WITH AN ARCCOS MAPPING OF THE HAMILTONIAN

2003 ◽  
Vol 02 (04) ◽  
pp. 547-551 ◽  
Author(s):  
PAOLO DEFAZIO ◽  
CARLO PETRONGOLO
Keyword(s):  
Rate Constant ◽  
Cross Sections ◽  
Room Temperature ◽  
Wave Packets ◽  
Flux Analysis ◽  
Title Reaction ◽  
Angular Momentum Quantum Number ◽  
Insertion Mechanism ◽  
Temperature Rate ◽  
Good Agreement

We have investigated the dynamics of the title reaction with the Gray and Balint-Kurti approach, which propagates real wave packets (WP) under an arccos mapping of a scaled and shifted Hamiltonian. We have considered H 2 rotational quanta j=0 and 1 and obtained reaction probabilities using reactant coordinates and the flux analysis. We have calculated accurate reaction probabilities for total angular momentum quantum number J=0, centrifugal-sudden probabilities for J>0, cross sections, and the room temperature rate constant. The present cross sections are in good agreement with previous quasiclassical trajectory (QCT) results and the theoretical rate constant compares rather well with that observed. WP snapshots show that the reaction occurs via a C2v insertion mechanism, confirming previous QCT calculations.

The dynamics of the Br + HgBr (v = 0, j = 0) → Br2 + Hg reaction based on quasi-classical trajectory calculations

2018 ◽  
Vol 96 (8) ◽  
pp. 926-932 ◽  
Author(s):  
Guan-Qing Ren ◽  
Ai-Ping Fu ◽  
Shu-Ping Yuan ◽  
Tian-Shu Chu
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Relative Velocity ◽  
Total Angular Momentum ◽  
Collision Energy ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Title Reaction ◽  
Trajectory Calculations ◽  
Angular Momentum Quantum Number

To investigate the dynamics mechanism of the Br + HgBr → Br2 + Hg reaction, the quasi-classical trajectory calculations are performed on Balabanov’s potential energy surface (PES) of ground electronic state. Both the scalar and vector properties are investigated to recognize the dynamics of the title reaction. Reaction probability for the total angular momentum quantum number J = 0 is determined at the collision energies (denoted as Ec) in a range of 1–25 kcal/mol, and the product vibrational distributions are given and compared between Ec = 20 and 40 kcal/mol. Other calculation values characterizing product polarizations including polarization-dependent differential cross sections (PDDCSs), distributions of P(θr), P([Formula: see text]), and P(θr, [Formula: see text]), are all discussed and compared between the two different collision energies in detail to analyze the alignment and orientation characteristics. It is revealed that the products prefer forward scattering and the PDDCSs are anisotropic in the whole range of the scattering angle. The product rotational angular momentum j′ shows a tendency to align perpendicular to the reagent relative velocity k. In fact, the product polarization of the title reaction is weak at both collision energies. In terms of horizontal comparison, the alignment is slightly stronger but the orientation is even less remarkable at higher collision energy.

EFFECTS OF ROTATIONAL AND VIBRATIONAL EXCITATION ON THE STEREODYNAMICS OF THE O (D-1) + HCl → OH + Cl REACTION

2009 ◽  
Vol 08 (06) ◽  
pp. 1177-1184 ◽  
Author(s):  
QIANG WEI ◽  
VICTOR WEI-KEH WU ◽  
BO ZHOU
Keyword(s):  
Cross Sections ◽  
Collision Energy ◽  
Energy Surface ◽  
Vibrational Excitation ◽  
Classical Trajectory ◽  
Rotational Excitation ◽  
Title Reaction ◽  
Vibrational Excitations ◽  
Product Vector ◽  
Good Agreement

The stereodynamics of the title reaction on the ground 1 1A′ potential energy surface (PES) has been studied using quasi-classical trajectory (QCT) method. Collision energy of 6.4 kcal/mol is considered, and vector properties including angular momentum alignment distributions and polarization-dependent differential cross-sections (PDDCS) of the product OH are presented. Furthermore, the influence of reagent rotational excitation and vibrational excitation on the product vector properties has also been studied in the present work. The results indicate that the distribution of the P(θr) and P(ϕr) are sensitively affected by the rotational and vibrational excitation. The rotational excitation decreases the degree of alignment and orientation, while vibrational excitation increases the degree of alignment and orientation. The PDDCS (2π/σ)(dσ20/dωt) and (2π/σ)(dσ22+/dωt) are sensitively influenced by rotational and vibrational excitations, while the PDDCS ((2π/σ)(dσ00/dωt)) and (2π/σ)(dσ21-/dωt) are not. The preference of forward scattering has been found from the results of PDDCS ((2π/σ)(dσ00/dωt)), which is in good agreement with the experimental results.

COMPARATIVE STUDY OF REACTION RATE CONSTANTS FOR THE NH3 + H → NH2 + H2 REACTION WITH GLOBE DYNAMICS AND TRANSITION STATE THEORIES

2009 ◽  
Vol 08 (06) ◽  
pp. 1227-1233 ◽  
Author(s):  
JU LIPING ◽  
LU RUIFENG
Keyword(s):  
Transition State ◽  
Cross Sections ◽  
Rate Constants ◽  
Quantum Dynamics ◽  
Classical Trajectory ◽  
State Theory ◽  
Title Reaction ◽  
Reaction Rate Constants ◽  
Barrier Type ◽  
Good Agreement

The nine-dimension quasi-classical trajectory (QCT) calculations have been carried out for the title reaction with a global potential energy surface (PES) constructed by Corchado and Espinosa-García (J Chem Phys106:4013, 1997). The detailed dynamics calculations cover the specific collision energies falling in the range of 0.62–3.04 eV, which are sufficient to fit the calculated reactive cross-sections into a barrier-type excitation function and to obtain the thermal rate constants. The present QCT rate constants are in good agreement with the recent quantum dynamics (QD) results, both of which are much lower than that of the previous variational transition state theory (VTST).

Room temperature rate constant for H+F 2

2002 ◽  
Author(s):  
Jiande Han ◽  
Gerald C. Manke II ◽  
Michael C. Heaven
Keyword(s):  
Rate Constant ◽  
Room Temperature ◽  
Temperature Rate

scholarly journals Temperature-(208–318 K) and pressure-(18–696 Torr) dependent rate coefficients for the reaction between OH and HNO<sub>3</sub>

2018 ◽  
Vol 18 (4) ◽  
pp. 2381-2394 ◽  
Author(s):  
Katrin Dulitz ◽  
Damien Amedro ◽  
Terry J. Dillon ◽  
Andrea Pozzer ◽  
John N. Crowley
Keyword(s):  
Cross Sections ◽  
Pressure Dependence ◽  
Low Temperatures ◽  
Room Temperature ◽  
Rate Coefficients ◽  
Title Reaction ◽  
Data Set ◽  
Dependent Rate ◽  
Temperature And Pressure

Abstract. Rate coefficients (k5) for the title reaction were obtained using pulsed laser photolytic generation of OH coupled to its detection by laser-induced fluorescence (PLP–LIF). More than 80 determinations of k5 were carried out in nitrogen or air bath gas at various temperatures and pressures. The accuracy of the rate coefficients obtained was enhanced by in situ measurement of the concentrations of both HNO3 reactant and NO2 impurity. The rate coefficients show both temperature and pressure dependence with a rapid increase in k5 at low temperatures. The pressure dependence was weak at room temperature but increased significantly at low temperatures. The entire data set was combined with selected literature values of k5 and parameterised using a combination of pressure-dependent and -independent terms to give an expression that covers the relevant pressure and temperature range for the atmosphere. A global model, using the new parameterisation for k5 rather than those presently accepted, indicated small but significant latitude- and altitude-dependent changes in the HNO3 ∕ NOx ratio of between −6 and +6 %. Effective HNO3 absorption cross sections (184.95 and 213.86 nm, units of cm2 molecule−1) were obtained as part of this work: σ213.86  =  4.52−0.12+0.23  ×  10−19 and σ184.95  =  1.61−0.04+0.08  ×  10−17.

scholarly journals Temperature (208–318 K) and pressure (18–696 Torr) dependent rate coefficients for the reaction between OH and HNO<sub>3</sub>

2017 ◽  
Author(s):  
Katrin Dulitz ◽  
Damien Amedro ◽  
Terry J. Dillon ◽  
Andrea Pozzer ◽  
John N. Crowley
Keyword(s):  
Cross Sections ◽  
Pressure Dependence ◽  
Low Temperatures ◽  
Room Temperature ◽  
Rate Coefficients ◽  
Title Reaction ◽  
Dependent Rate ◽  
Temperature And Pressure ◽  
Entire Dataset

Abstract. Rate coefficients (k5) for the title reaction were obtained using pulsed laser photolytic generation of OH coupled to its detection by laser-induced fluorescence (PLP-LIF). More than eighty determinations of k5 were carried out in nitrogen or air bath gas at various temperatures and pressures. The accuracy of the rate coefficients obtained was enhanced by in-situ measurement of the concentrations of both HNO3 reactant and NO2 impurity. The rate coefficients show both temperature and pressure dependence with a rapid increase in k5 at low temperatures. The pressure dependence was weak at room temperature but increased significantly at low temperatures. The entire dataset was combined with selected literature values of k5 and parameterised using a combination of pressure dependent and independent terms to give an expression that covers the relevant pressure and temperature range for the atmosphere. A global model, using the new parameterisation for k5 rather than those presently accepted, indicated small but significant latitude and altitude dependent changes in the HNO3 / NOx ratio of between −6 % and +6 %. Effective HNO3 absorption cross sections (184.95 and 213.86 nm, units of cm2 molecule−1) were obtained as part of this work: σ213.86 = 4.52+0.23−0.12 × 10−19 and σ184.95 = 1.61+0.08−0.04 × 10−17.

Mesure de la constante de vitesse de réaction des atomes d'hydrogène sur l'éthane et le propane en réacteurs tubulaire et parfaitement agité ouverts

1978 ◽  
Vol 56 (3) ◽  
pp. 392-401 ◽  
Author(s):  
Jacques Lede ◽  
Jacques Villermaux
Keyword(s):  
Hydrogen Atom ◽  
Rate Constant ◽  
Electrical Discharge ◽  
Room Temperature ◽  
Hydrogen Atoms ◽  
Atom Concentration ◽  
Sensitive Method ◽  
Good Agreement

The rate constant for the reaction of hydrogen atoms, generated by electrical discharge, with ethane and propane has been studied in tubular and perfectly stirred open reactors. Measurements are made with a new and very sensitive method of analysis of the hydrogen atom concentration. The results obtained near room temperature are in good agreement with those of other authors operating at much higher temperatures. The following estimates may be made:[Formula: see text]

Measurement and Modeling of Intrinsic Stresses in CVD W Lines

1995 ◽  
Vol 391 ◽  
Author(s):  
Jin Lee ◽  
Qing Ma ◽  
Thomas Marieb ◽  
Anne S. Mack ◽  
Harry Fujimoto ◽  
...  
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Intrinsic Stress ◽  
X Ray ◽  
Chemical Vapor Deposited ◽  
Biaxial Tensile Stress ◽  
Stress States ◽  
Good Agreement

AbstractWe have studied stress states in chemical vapor deposited (CVD) tungsten (W) for both blanket films and lines, to understand better the mechanical implications of intrinsic stress for interconnection structures. Since W has a low mobility at its deposition temperature, a very large intrinsic stress develops during deposition. Intrinsic strains in blanket W films were measured with an X-ray technique. The measured strains correspond to a biaxial tensile stress of the order of 1 GPa. This result was used to provide an initial strain input in a finite element calculation to obtain intrinsic stress states in W lines. SEM observation of cross sections of the metal lines enabled us to determine the growth pattern of the W, and infer the boundary conditions during growth. Finite Element Method (FEM) calculations of the room temperature stress in the lines, including both intrinsic and thermal components, are in good agreement with X-ray determinations.

SELENIUM ISOTOPE EFFECTS IN THE REDUCTION OF SODIUM SELENITE AND OF SODIUM SELENATE

1966 ◽  
Vol 44 (4) ◽  
pp. 419-427 ◽  
Author(s):  
C. E. Rees ◽  
H. G. Thode
Keyword(s):  
Rate Constant ◽  
Sodium Selenite ◽  
Room Temperature ◽  
Isotope Effects ◽  
Sodium Selenate ◽  
Theoretical Predictions ◽  
Selenium Isotope ◽  
Use Of Models ◽  
Good Agreement

Selenium isotope effects in the reduction of sodium selenite and of sodium selenate have been studied. Rate constant ratios for the 76Se and 82Se species have been determined for the reactions Seiv → Se0 (1.017), Sevi → Seiv (1.018), and Se0 → Seiv (1.010) at room temperature. Theoretical predictions of the first two ratios, from the use of models in which the rate-controlling steps are assumed to be Se—O bond cleavages in SeO32− and SeO42−, respectively, lead to predictions in good agreement with experiment.

Sign in / Sign up

Export Citation Format

Share Document