Ab Initio Study on the Reaction of La~+ + CH_4→La+-CH~2 + H_2

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Ab Initio Studies on the Structure and Binding Interaction of M~ CO_2(M=Sc,Ti…Zn)

ＡｂＩｎｉｔｉｏＳｔｕｄｉｅｓｏｎｔｈｅＳｔｒｕｃｔｕｒｅａｎｄＢｉｎｄｉｎｇＩｎｔｅｒａｃｔｉｏｎｏｆＭ＋ＣＯ２（Ｍ＝Ｓｃ,Ｔｉ…Ｚｎ）＊ＦＡＮＨｏｎｇ－Ｊｕｎ,ＺＨＯＮＧＳｈｉ－Ｊｕｎ,ＬＩＵＣｈｕｎ－Ｗａｎ＊＊（ＦｕｊｉａｎＩｎｓｔｉｔｕｔｅｏ...     

Ab initio Study on the Interaction of La (Ⅲ) with Adrenaline

IntroductionInrecentyears,thebiologlcaIeffectsofrareearthshavcbeendsdsedestensiveyinChina.IthasbecnfoundthatrareearthsshowintcreedngneuralandendocrineeffeCtlll.Thermdyontheintcractionofrareearth8withhormoncisveryhoportanttoclariopgthencuralandendocrinceffecofrareearth8anditsmeckanism.Adrenalineisavitalkindofhormone.ThermdiesoncomplexesofmstaiionswithadrenalinhavebecnrePOrted12'4l.Bowever,whichgroupofadrenalinescrvesasdonorhasbeenund6rcoatmersyforalongtimc.Thus,theinteractionofLa(III)witba…     

Theoretical Studies on CH_3SiH_3 H→CH_3SiH_2 H_2 Reaction with the Variational Transitional State Theory

IntroductionThe abstraction reaction between CH,SiH, and H plays an important role in siliconcontaining species and has been the subject of many experimental studies'-', but it hasnot been studied with the variational transition state theory. In this paper, the dynamics ofthe title reaction is investigated by using POLYRATE7.8 program obtained from Truhlar'.The theoretical rate constants for the title reaction are obtained over a wide range oftemperature 298- 1 700 K.Theory and Methods'…     

Ab initio study of the complexes of first-row transition-metal ions with CH, CH_2, and CH_3

The geometries and bonding characteristics of the complexes of the first-row transition-metal ions with CH, CH_2 and CH_3 were investigated by ab initio molecular orbital theory. MCH~ and MCH_2~ are linear and coplanar, re spectively. Both of them are with obvious treble or double bond characteristics, but these multiple bonds are mostly "im perfect". The calculated bond dissociation energies of C--M~ , C=M~ and C≡M~ are mostly close to the experi mental values, and appear in similar periodic trends from Sc to Zn.     

Ab initio studies on reaction H_2C═C(OH)Li+CH_3~+(CH_3~-)

Ｃａｒｂｅｎｏｉｄｓａｎｄｃｏｍｐｏｕｎｄｓｗｉｔｈｃａｒｂｅｎｏｉｄｎａｔｕｒｅａｒｅｏｆｓｐｅｃｉａｌｉｎｔｅｒｅｓｔｓｙｎｔｈｅｔｉｃａｌｌｙ.ＴｈｅｓｅｃｏｍｐｏｕｎｄｓｒｅａｃｔｎｏｔｏｎｌｙｗｉｔｈｅｌｅｃｔｒｏｐｈｉｌｅｓＥ(ａｓａｌｌ“ｃａｒｂａｎｉｏｎｓ”ｄｏ),ｂｕｔａｌｓｏｗｉｔｈｎｕｃｌｅｏｐｈｉｌｅｓｌｉｋｅＲＬｉ.Ｔｈｅａｍｂｉｄｅｎｔｎａｔｕｒｅｏｆｃａｒｂｅｎｏｉｄｓｈａｓｌｅｄｔｏｍａｎｙｉｎｖｅｓｔｉｇａｔｉｏｎｓｏｆｔｈｅｉｒｓｔｒｕｃｔｕｒｅｓａｎｄｉｓｏｍｅ…     

Ab initio Mechanism Study on the Reaction of Chlorine Atom with Formic Acid

The potential energy surface(PES) for the reaction of Cl atom with HCOOH is predicted using ab initio molecular orbital calculation methods at UQCIDS(T,full)6-311 G(3df,2p)//UMP2(full)/6-311 G(d,P) level of theory with zero-point vibrational energy (ZPVE) correction.The calculated results show that the reaction mechanism of Cl atom with formic acid is a C-site hydrogen abstraction reaction from cis-HOC(H)O molecule by Cl atom with a 3.73kJ/mol reaction barrier height,leading to the formation of cis-HOCO radical which will reacts with Cl atom or other molecules in such a reaction system.Because the reaction barrier height of O-site hydrogen abstraction reaction from cis-HOC(H)O molecule by Cl atom which leads to the formation of HCO2 radical is 67.95kJ/mol,it is a secondary reaction channel in experiment,This is in good agreement with the prediction based on the previous experiments.     

A Detailed Dynamics Study of the Reaction CH_4 Cl→HCl CH_3

Recently,XuebinWangetal.'studiedthereactionofCH4(v=l,j=l) Cl-HCl CH3usingthequasiclassicaltrajectoryapproachontheLondon-Eyring-Polany-Sato(LEPS)potentialenergysurface(PES).Theirresultsshowedgoodagreementwiththeexperimental.alues2.However,thedetaileddynndcsofthisreactionwasnotavaiIableintheirstudy,suchastheeffectofthereactants'rotationalstateandvibrationalstateonthereaction.Inthiswork,wecarryouta3Dquasiclassicaltrajectorycalculation,andprovideaclearerpictureofthisreaction.ComPututiona…     

Theoretical studies on the reaction path and dynamics of the reaction CH_3+H_2O→CH_4+OH

The reaction path, the dynamical properties along the reaction path and CVT rate constants are computed by the ab initio MO method, the reaction path Hamiltonian theory and the variational transition state theory. The results show that the effect of the electron correlation energy on activation barrier is large, the recrossing and tunneling effects exist in the reaction.     

Ab Initio Studies on the [Os(PR_3)_4H(H_2)]~+ System

The [Os(PH3)4H(H2)]+ system was studied using the Gaussian 88 and the energy gradient technique at the restricted Hartree-Fock level under the effective core potential (ECP) approximation. The two different isomers of complex [Os(PH3)4H (H2)] (cis and trans) were optimized, and several orientations of the hydrogen molecule were considered for the cis isomer. When the hydride is placed in the cis position and oriented suitably, there is a strongly attractive effect between it and the molecular hydrogen.     

Direct Dynamics Study on CH_2O + CH_3~·→ CHO + CH_4 Reaction

It is still a formidable challenge to study CH2O CH3·→ CHO CH4 reaction in the gas phase by traditional dynamics, because of the large number of freedom degrees for the system. In this paper, direct dynamics, in which trajectories were run directly on the DFT potential energy surface, have been applied to the reaction, which gave a direct look in the reaction processes. Two sets of trajectories at different initial orientations of reactants and temperature have been simulated. And the detailed reaction mechanisms have been described.     

Ab Initio Study of the Reaction: H SO_2→HO SO

Intr0ducti0nThereactionofvariousmolecularandatomicspecieswithsulfurdioxidehasbeenthesubjectofmanykineticstudiesmainIybecauseofitsinvolvementinmany0fthechemi-calreacti0ns0ccurringintheupperatmosphereandals0becauseofitsindustrialsignifi-cance.I-2Theintermediatesinv0lvedinthereactionareusuallynotdirectlyobservable.Forexample,thegeometryoftheSO2.Hadductisuncertain.TwopossiblestructUreshavetheHat0mbondedeithert0theSat0m,representedasHSO2,orbondedtoan0atom,representedasHOSO.ThestructUresaresh…     

Ab initio study on the mechanism of reaction HNCO+NH_2

Ab initio UMP2 and UQCISD(T) calculations, with 6-311G** basis sets, were performed for the titled reactions. The results show that the reactions have two product channels: NH2+ HNCO→NH3+NCO (1) and NH2+HNCO-N2H3+CO (2), where reaction (1) is a hydrogen abstraction reaction via an H-bonded complex (HBC), lowering the energy by 32.48 kJ/mol relative to reactants. The calculated QCISD(T)//MP2(full) energy barrier is 29.04 kJ/mol, which is in excellent accordance with the experimental value of 29.09 kJ/mol. In the range of reaction temperature 2300-2700 K, transition theory rate constant for reaction (1) is 1.68 × 1011- 3.29 × 1011 mL · mol-1· s-1, which is close to the experimental one of 5.0 ×1011 mL× mol-1· s-1 or less. However, reaction (2) is a stepwise reaction proceeding via two orientation modes, cis and trans, and the energy barriers for the rate-control step at our best calculations are 92.79 kJ/mol (for cis-mode) and 147.43 kJ/mol (for trans-mode), respectively, which is much higher than     

Studies on the Reaction of Benzopyran-4-one with Hydroxylamine Hydrochloride

GreatattentionshavebeentwdtopotalsiumchannelOpenerspeOs)fortheirnovelmechosminthetreatmentOfCardiovasculardiseases.BenZOPyran-4oneisakeyintermedjatefOrpreParillgbenzOWan'sPCOs,chchisthemoStimPOrtantStruCtUraltypeOfPCOs.Inordertoobtalnsomebenz~-4oneoximeanalOgUes,6nitro-benZOPyran-4oneltaledwithhydrOxyltalnehydrochlorideintwdineattemperatureaccOndngtoconunonSyntheticmethodaInixtUre(lfl)ofbenzOPyran-4oneoxime2andisoxazoline3wereproduced.No-ltisrePOrtedthat6-methyl-flavanone4whentr…     

Ab initio second-order Møller-Plesset calculation of the vibrational spectra of C4 clusters

Second-order Møller-Plesset calculations on the C₄ potential surface yielded three isomers, a linear triplet and rhombic and tetrahedral singlets. A large discrepancy between observed and calculated frequencies of the Σ_u⁺ vibration of linear ¹²C₄ is outside the expected range of error. It is tentatively suggested that an observed absorption at 1544 cm⁻¹ previously assigned to C₅ might belong instead to C₄.     

Thermodynamic investigation on M–Te–O (M = Sc, Y) system

The standard Gibbs energy of formation of M₂TeO₆ and M₆TeO₁₂ (where M = Sc, Y), was determined from its vapor pressure measurements by employing thermogravimetry-based transpiration technique. This technique was validated by measuring the vapor pressure of well-studied substances such as TeO₂(s) and CdCl₂(s). The temperature dependence of the vapor pressure of TeO₂(g) over the mixtures M₆TeO₁₂ + M₂O₃ (where M = Sc, Y), generated by the incongruent vaporization reaction, M₆TeO₁₂(s) → 3M₂O₃(s) + TeO₂(g) + ½O₂(g) were measured in the temperature range 1,413–1,473 K and 1,623–1,743 K for Sc₆TeO₁₂(s) and Y₆TeO₁₂(s), respectively. Similarly, the vapor pressure of TeO₂(g) over the mixtures M₂TeO₆(s) + M₆TeO₁₂(s) generated by the vaporization reaction, 3M₂TeO₆(s) → M₆TeO₁₂(s) + 2TeO₂(g) + O₂(g) was measured in the temperature range (1,223–1,293 K) and (1,333–1,423 K) for Sc₂TeO₆(s) and Y₂TeO₆(s), respectively. From the vapor pressure measurements, the standard Gibbs energy of formation of M₆TeO₁₂ and M₂TeO₆ were derived.     

Theoretical Studies on the Intermonomer Interaction of F~-·(H_2O)_n (n = 1, 2)

1 INTRODUCTION Hydrogen bond plays an important role in the fields of physics, biology and chemistry. It has cap- tured the interest of chemists for a long time and reports about its theory and experiment have been well represented[1～6]. Concerning its theoretical inves- tigations, most of the emphases are placed on the weak interaction energy of intramolecular hydrogen bond. But studies on its spectrum behavior are rela- tively rare. These years spectrum behavior led by hydrogen bond h…     

Ab initio study on the dynamical properties of the hydrogen abstraction reaction NH2 + OH → NH + H2O

 The geometry of the transition state of the title reaction was optimized at the unrestricted Hartree–Fock, the spin-unrestricted second-order M?ller–Plesset, and the spin-unrestricted quadratic configuration interaction with all single and double substitutions levels of theory. The changes in the geometry, the bound vibrational modes, and the potential energy along the minimum energy path are discussed. Variational transition-state theory rate constants calculated with the tunneling and curvature effect correction agree very well with the experimental values. Received: 23 April 1999 / Accepted: 9 June 1999 / Published online: 15 December 1999     

Studies on Mechanism of Chemiluminescence Reaction of 2, 6, 7-Trihydroxyl-9-(4'-chlorophenyl )-3-fluorone

1INTRoDUCTIONPhenylfluoroneisanimportanttypeofreagentinanalytica1chemistry"~'>.Themoleculesofthisreagenthavearigidplanarstructuret5'6i,sotheenergyofmolecularorbitsofthereagentscanbecalculatedbyHuckelmolecularorbitalmethod(HMO).WehadtriedtoassigndissociationconstantsforsomesuchreagentsbyacombinedspectrophotometricandHMOmethodt7'8i.Them.thodissimpleandtheresultsaresatisfactory.Inthispaper,apossiblemechanismforcatalyticchemiluminescencere-actionofCl-PFisproposedonthebasisofstudyingchemil…     

Ab Initio Studies on Eight Electronic States of the BH_2 Radical

The present paper covers ab initio UHF calculations with a d, p-polarized basis set performed for eight electronic states of BH2 and the equilibrium geometries, electronic term values Tc and vibrational frequencies of the five stable states X2A1, 2B1, 2B2, 22A1 and 2A2. On the basis of the UHF results, the states 22B2. 2B1 and 32A1 are predicted to be unstable. The MP2/6-31G * * calculations were performed for the X2A1 and 2B1, states, and the calculated equilibrium geometries, Tc value and vibrational frequencies are similar to the UHF results. The MP2/6-31G * * studies on the reaction BH2→BH + H for the X2A1 and 2B1 states were carried out and the HB-H bond energies of these two states were calculated.