Vector correlations study of the reaction N(~2D) + H_2(X^1Σ_g^+) →NH(a^1?) + H(~2S) with different collision energies and reagent vibration excitations

Vector correlations of the reaction N（2D） ＋H2（X1∑g＋） NH（a1△）→ ＋ H（2S） are studied based on a recent DMBE- SEC PES for the first excited state ofNH2 [J. Phys. Chem. A 114 9644 （2010）] by using a quasi-classical trajectory method. The effects of collision energy and the reagent initial vibrational excitation on cross section and product polarization are investigated for v = 0-5 and j = 0 states in a wide collision energy range （10-50 kcal/mol）. The integral cross section could be increased by H2 vibration excitation remarkably based on the DMBE-SEC PES. The different phenomena of differential cross sections with different collision energies and reagent vibration excitations are explained. Particularly, the NH molecules are scattered mainly in the backward hemisphere at low vibration quantum number and evolve from backward to forward direction with increasing vibration quantum number, which could be explained by the fact that the vibrational excitation enlarges the H-H distance in the entrance channel, thus enhancing the probability of collision between N atom and H atom. A further study on product polarization demonstrates that the collision energy and vibrational excitation of the reagent remarkably influence the distributions of P（Or）, P（（Pr）, and P（Or, （Pr）.

QSAR of Estrogen of Bisphenol A with 3D Vector of Atomic Property Correlation

Considering atomic property vector and atomic correlative function, the 3-dimensional structural vector of atomic property correlation （3D-VAPC）, a novel descriptor,is defined to characterize a 3-dimensional molecular structure by introducing self-adaptability regulation mechanism and the idea of orientating to customers. Characterizing the structures of 25 bisphenol A compounds by this vector, the QSAR models of three kinds of estrogen activities （ER affinities, gene induction and cell proliferation） have high multiple correlation coefficient （Rcum^2=0.933, 0.813, 0.959） and cross verification coefficient （Qcum^2=0.847, 0.953, 0.798） by support vector machine （SVM）, which suits for nonlinear circumstances. The above results show that the models successfully express the correlation between structure and three kinds of estrogen activities. Therefore, 3D-VAPC exactly reflects the molecular structural information and SVM method correctly describes the correlation between information and property of the compounds.

Influence of rotational excitation and collision energy on the stereo dynamics of the reaction:N(~4S)+H_2 (v=0,j=0,2,5,10)→NH(X^3Σ^-)+H

The N＋H2 reaction has attracted a great deal of attention from both the experimental and the theoretical community, and most of the attention has been paid to the first excited state N （2 D） atoms in collisions with hydrogen molecules and the scalar properties of the reaction. In this paper, we study the stereo dynamical properties and calculate the reaction cross sections of the N（4S） ＋ H2 （v=0, j=0, 2, 5, 10） → NH（X3∑-） ＋ H using the quasi-classical trajectory （QCT） method on an accurate NH2 potential energy surface （PES） reported by Poveda and Varandas [Poveda L A and Varandas A J C 2005 Phys. Chem. Chem. Phys. 7 28671, in a collision energy range of 25 kcal.mol-1 -140 kcal.mol-1. Results indicate that the reactant rotational excitation and initial collision energy both have a considerable influence on the distributions of the k-j＇ correlation, the k-k＇-j＇ correlation and k-k＇ correlation. The differential cross section is found to be sensitive to collision energy.

Stereodynamics study of reactions N（2D）＋HD→NH＋D and ND＋H

The product polarizations of the title reactions are investigated by employing the quasi-classical trajectory （QCT） method. The four generalized polarization-dependent differential cross-sections （PDDCSs） （2π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dωt）, （2π/σ）（dσ22＋/dωt）, and （2π/σ）（dσ21-/dωt） are calculated in the centre-of-mass frame. The distribution of the angle between κ and j＇, P（θr）, the distribution of the dihedral angle denoting κ-κ＇-j＇ correlation, P（Фr）, as well as the angular distribution of product rotational vectors in the form of polar plots P（θr, Фr） are calculated. The isotope effect is also revealed and primarily attributed to the difference in mass factor between the two title reactions.

Effects of the vibrational and rotational excitation of reagent on the stereodynamics of the reaction S (3P) ＋ H2→ SH ＋ H

Quasiclassical trajectory （QCT） calculations are first carried out to study the stereodynamics of the S （3p） ＋ H2 → SH ＋ H reaction based on the ab initio 13Atr potential energy surface （PES） （Lii etal. 2012 J. Chem. Phys. 136 094308）. The QCT-calculated reaction probabilities and cross sections for the S ＋ H2 （v = 0, j = 0） reaction are in good agreement with the previous quantum mechanics （QM） results. The vector properties including the alignment, orientation, and polarization- dependent differential cross sections （PDDCSs） of the product SH are presented at a collision energy of 1.8 eV. The effects of the vibrational and rotational excitations of reagent on the stereodynamics are also investigated and discussed in the present work. The calculated QCT results indicate that the vibrational and rotational excitations of reagent play an important role in determining the stereodynamic properties of the title reaction.

Effect of the reagent vibration on stereodynamics of the reaction O（^1D）＋HF→F＋OH

This paper studies the influence of the reagent vibration on the reaction O（1D）＋HF→HO＋F by using a quasiclassical trajectory method on the new ab initio 1A＇ ground singlet potential energy surface （Gomez-Carrasco et al 2007 Chem. Phys. Lett. 435 188 193）. The product angular distributions which reflect the vector correlation are calculated. Four polarization-dependent differential cross sections （PDDCSs） which are sensitive to many photoinitiated bimolecular reaction experiments are presented in the center of the mass frame, respectively. The differential cross section indicates that the OH product mainly tends to the forward scattering, and other PDDCSs are also influenced by the vibration levels of HF.

The effect of the rotational excitation of NO on the stereodynamics for the reaction C(~3P)+NO(X^2Π)→CN(X^2Σ^+)+O(~3P)

The stereodynamic properties of the reaction C （^3P） ＋ NO （X2^П） →CN （X^2∑^＋） ＋ O （^3P） in different rotational states of reactant NO are studied theoretically by using the quasiclassical trajectory method on ^2A″ and ^2A′ potential energy surfaces （PESs） at a collision energy of 0.06 eV. The vector properties in different rotational states on the two surfaces are discussed in detail. The results indicate that the rotational excitation of NO has considerable influence on the stereodynamic property of the reaction occurring on the two surfaces. At the same time, the calculated polarization-dependent differential cross sections （PDDCSs） in different initial rotational states manifest that products are strongly polarized at three scattering angles.

Influence of the reagent vibration on the stereodynamics of the reactions D^-+H_2 and H^-+D_2

Employing the quasi-classical trajectory method and the potential energy surface of Panda and Sathyamurhy [Panda A N and Sathyamurthy N 2004 J. Chem. Phys. 121 9343], the effect of the reagent vibration on vector correlation of the ion-molecule reactions D- ＋ H2 and H- ＋ D2 is studied at a collision energy of 35.7 kcal/mol. Four generalized polarization-dependent differential cross sections （2π/σ） （dσ00/dωt）, （2π/σ） （dσ20/dσ20）, （27π/σ） （dσ22＋/dwt）, and （2π/σ）（dπ/σ） are presented in the centre-of-mass reference frame, separately. At the same time, the effects on the product angular distributions P（θr）, P（~r） and P（Oφ） of the title reactions are also analysed. The calculated results show that the scattering tendencies of the product HD, the alignment and the orientation of j^1 sensitively depend on reagent molecule vibration.

A theoretical study of the stereodynamics on the abstraction reactions H/D+HS/DS

The quasi-classical trajectory （QCT） method is employed to calculate the stereodynamics of the abstraction reactions H/D ＋ HS/DS based on an accurate potential energy surface [Lti S J, Zhang P Y, Han K L and He G Z 2012 J. Chem. Phys. 136 094308]. The reaction cross sections of the title reaction are computed, and the vector correlations for different collision energies and different initial vibrational states are presented. The influences of the collision energy and reagent vibration on the product polarization are studied, and the product polarizations of the title reactions are found to be distinctly different, which arises from the different mass factors, collision energies, and reagent vibrational states.

The collision energy effect on the stereodynamics of the Ca + HCl→CaCl + H reaction

The stereodynamics of the reaction of Ca ＋ HCl are calculated at three different collision energies based on the potential energy surface [Verbockhaven G et al. 2005 J. Chem. Phys. 122 204307] using quasi-classical trajectory theory. The polarization-dependent differential cross sections （PDDCSs） （2π/σ ）（dσ 00 /dω t ）, （2π/σ ）（dσ 20 /dωt ）, （2π/σ ）（dσ 22＋ /dωt ）, （2π/σ ）（dσ 21 /dω t ） and the distributions of P（θ r ）, P（φr ）, and P（θr ,φr ） are calculated. The results indicate that the rotational polarization of the CaCl product presents different characteristics for the different collision energies, and the effects of the collision energy on the vector potential, including the alignment, orientation, and PDDCSs, are not obvious.

The polarization dependent differential cross sections of the reactions:H+LiH^+(v=0,j=0)→H_2+Li^+ and H^++ LiH(v=0,j=0)→H_2^++Li

Quasi-classical trajectory(QCT) calculations have been carried out to study the generalized polarization dependent differentialcross sections(PDDCSs) for the reactions H + LiH^+(v = 0,j = 0)→H_2 + Li^+ and H^+ + LiH(v = 0,j = 0)→H_2^+ + Li occurring onthe two lowest-lying electronic states of the LiH_2^+ system,using the ab initio potential energy surfaces(PESs) of Martinazzo et al.[3].Four PDDCSs,i.e.,(2π/σ)(dσ_(00)/dω_t),(2π/σ)(dσ_(20)/dω_t),(2π/σ)(dσ_(22+)/dω_t),(2π/σ)(dσ_(21-)/dω_t) have been discussed ...

The effect of collision energy on the stereodynamics of the reaction H(~2S)+NH(X^3∑^-,v = 0,j = 0)→ N(~4S)+H_2

The quasi-classical trajectory （QCT） is calculated to study the stereodynamics properties of the title reaction H（^2S） ＋ NH （X^3 ∑^-, v = 0, j = 0）→ N（^4S） ＋ H2 on the ground state ^4A″ potential energy surface （PES） constructed by Zhai and Han [2011 Jr. Chem. Phys. 135 104314]. The calculated QCT reaction probabilities and cross sections are in good agreement with the previous theoretical results. The effects of the collision energy on the k-kt distribution and the product polarization of H2 are studied in detail. It is found that the scattering direction of the product is strongly dependent on the collision energy. With the increase in the collision energy, the scattering directions of the products change from backward scattering to forward scattering. The distribution of P（Or） is strongly dependent on the collision energy below the lower collision energy （about 11.53 kcal/mol）. In addition, the P（（Pr） distribution dramatically changes as the collision energy increases. The calculated QCT results indicate that the collision energy plays an important role in determining the stereodynamics of the title reaction.

Theoretical study of stereodynamics for the reaction O(3P) ＋D2 (v=0, j=0) →OD＋D and isotope effect

Quasi-classical trajectory （QCT） calculations have been performed to study the product polarization behaviours in the reaction O（3p） ＋ D2 （v = 0, j = 0） → OD ＋ D. By running trajectories on the 3A′ and 3A″potential energy surfaces （PESs）, vector correlations such as the distributions of the polarization-dependent differential cross sections （PDDCSs）, the angular distributions of P（θr） and P（Фr） are presented. Isotope effect is discussed in this work by a comprehensive comparison with the reaction O（3p） ＋ H2 （v = 0, j = 0） → H ＋ H. Common characteristics as well as differences are discussed in product alignment and orientation for the two reactions. The isotope mass effect differs on the two potential energy surfaces： the isotope mass effect has stronger influence on P（θr） and PDDCSs of the 3A′ PES while the opposite on P（Фr） of the 3A′ potential energy surface.

Effects of collision energy and rotational quantum number on stereodynamics of the reactions:H(~2S)+NH(v=0,j=0,2,5,10)→N(~4S)+H_2

The stereodynamical properties of H（^2S） ＋ NH（v = 0,j = 0,2,5,10）→N（^4S） ＋ H2 reactions are studied in this paper by using the quasi-classical trajectory（QCT） method with different collision energies on the double many-body expansion（DMBE） potential energy surface（PES）（Poveda L A and Varandas A J C 2005 Phys.Chem.Chem.Phys.7 2867）.In a range of collision energy from 2 to 20 kcal/mol,the vibrational rotational quantum numbers of the NH molecules are specifically investigated on v = 0 and j = 0,2,5,10 respectively.The distributions of P（θr）,P（φr）,P（θr,φr）,（2π/σ）（dσ（00）/dωt）differential cross-section（DCSs） and integral cross-sections（ICSs） are calculated.The ICSs,computed for collision energies from 2 kcal/mol to 20 kcal/mol,for the ground state are in good agreement with the cited data.The results show that the reagent rotational quantum number and initial collision energy both have a significant effect on the distributions of the k-j＇,the k-k＇-j＇,and the k-k＇ correlations.In addition,the DCS is found to be susceptible to collision energy,but it is not significantly affected by the rotational excitation of reagent.

Theoretical study of stereodynamics for reaction O（3p）＋HCl

The vector correlation between products and reagents for reaction O（3P）＋HCl→OH＋Cl is studied using a quasi- classical trajectory （QCT） method on the benchmark potential energy surface of the ground 3A″ state [Ramachandran and Peterson, J. Chem. Phys. 119 （2003） 9550]. The generalised differential cross section （2π/σ）（dσ00/dwt） is presented in the centre of mass frame. The distribution of dihedral angles, P（Фr）, and the distribution of angles between k and j′, P（θr）, are calculated. The influence of the collision energy and the influence of the reagent rotation and vibration on the product polarization are studied in the present work. The calculated results indicate that the rotational polarization of product molecule is almost independent of collision energy but sensitive to the reagent rotation and vibration. product rotational polarization, vector correlations, differential cross sections, quasi- classical trajectory

Quasi-classical trajectory approach to the O(~1D)+HBr→OH+Br reaction stereo-dynamics on X^1A'potential energy surface

The vector properties of reaction O（1D）＋HBr→OH＋Br on the potential energy surface （PES） of X1A＇ ground singlet state are studied by using the quasi-classical trajectory （QCT） theory. The polarization-dependent differential cross sections （PDDCSs）, the average rotational alignment factor （P 2 （j＇- k）〉, as well as the distributions reflecting vector correlations are also computed. The analysis of the results shows that the alignment and the orientation distribution of the rotation angular momentum vector of product molecule OH is influenced by both the effect of heavy-light heavy （HLH） type mass combination and the deep well of PES.

Influence of reagent vibration on the stereodynamics of the Li+HF→LiF+H reaction

We investigate the influence of reagent vibration on the stereodynamics of the title reaction by the quasi-classmal trajectory on the Aguado-Paniagua2-potential energy surface developed by Aguado et al. （J. Chem. Phys. 1997 106 1013）. The cross sections and reaction probability as functions of the reagent vibration are calculated in the centre-of- mass frame. The product angular distributions of p（Фr）, p（Фr）, and p（Фr, Фr）, which reflect the vector correlation, are also presented and discussed. The results indicate that the vector properties are sensitively affected by the vibrational excitation.

Stereodynamics of the reactions Ne+H_2^+/Ne+D_2^+/Ne+T_2

The vector correlations between products and reagents for the reactions Ne＋H2＋, Ne＋D2＋, and Ne＋T2＋ are calculated by means of the quasi-classical trajectory method on a new potential energy surface constructed by Lfi et al, [J. Chem. Phys. 2010 132, 014303]. The polarization-dependent differential cross-sections （27π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dwt）, （27π/σ）（dσ22＋/dwt）, and （2π/σ）（dσ21-/dwt）, and the distributions of P（θr）, P（φ）, and P（θr, Cr） are calculated. The isotopic effect, which is associated with the difference in mass factor among the three reactions, is revealed.

Stereo-dynamics of the exchange reaction H_a+LiH_b→LiH_a+H_b and its isotopic variants

The quasi-classical trajectory （QCT） method is used to calculate the stereo-dynamics of the exchange reaction Ha＋LiHb→LiHa＋Hb and its isotopic variants based on an accurate potential energy surface reported by Prudente et al. [Prudente F V, Marques J M C and Maniero A M 2009 Chem. Phys. Lett. 474 18]. The reactive probability of the title reaction is computed. The vector correlations and four polarization-dependent generalized differential cross sections （PDDCSs） at different collision energies are presented. The influences of the collision energy and the reagent rotation on the product polarization are studied in the present work. The results indicate that the product rotational angular momentum j′ is not only aligned, but also oriented along the direction perpendicular to the scattering plane. The product polarization distributions of the title reaction and its isotopic variants exhibit distinct differences which may arise from different mass combinations.

Stereodynamics of the O(~3P) with H_2(D_2) (ν=0,j=0) reaction

Quasi-classical trajectory theory is used to study the reaction of O（3p） with H2 （D2） based on the ground 3A″ potential energy surface （PES）. The reaction cross section of the reaction O＋H2→＋OH＋H is in excellent agreement with the previous result. Vector correlations, product rotational alignment parameters （P2（j′. k）） and several polarizeddependent differential cross sections are further calculated for the reaction. The product polarization distribution exhibits different characteristics that can be ascribed to different motion paths on the PES, arising from various collision energies or mass factors.