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1988 Volume 4 Issue 6
1988, 4(06): 561-565
doi: 10.3866/PKU.WHXB19880601
Abstract:
The interaction between superconducting thin film of YBa_2Cu_3O_(7_δ) and substrate Of YSZ (Yttric stabilized zirconia) was investigated by AES. It is found after annealing at 900 ℃ that Ba and Cu atoms in the film severely diffuse to and interact with the substrate, white Zr atoms of the substrate do to and with the film, moreover,the diffusion of Ba atoms is more rapid than that of Cu atoms. A thin Ag film deposited on the substrate as a buffer layer seperates the defects on the surface of substrate from the film to suppress the formation of the second phases at the substrate defects as nucleation centre and retard the diffusion of Ba and Cu atoms to the substrate, and lessen the segregation of Cu and CuO in the film.
The interaction between superconducting thin film of YBa_2Cu_3O_(7_δ) and substrate Of YSZ (Yttric stabilized zirconia) was investigated by AES. It is found after annealing at 900 ℃ that Ba and Cu atoms in the film severely diffuse to and interact with the substrate, white Zr atoms of the substrate do to and with the film, moreover,the diffusion of Ba atoms is more rapid than that of Cu atoms. A thin Ag film deposited on the substrate as a buffer layer seperates the defects on the surface of substrate from the film to suppress the formation of the second phases at the substrate defects as nucleation centre and retard the diffusion of Ba and Cu atoms to the substrate, and lessen the segregation of Cu and CuO in the film.
1988, 4(06): 566-571
doi: 10.3866/PKU.WHXB19880602
Abstract:
This paper deals with the weak ligand field of d-shell by use of the unitary group approach (UGA). It specially discusses how to construct symmetry functions adapted to the group chain U(5)>SO(5)>SO(3)>G. The functions are built up using the Lie algebraic technique and expressed in terms of Gelfand states of the (5) group.
This paper deals with the weak ligand field of d-shell by use of the unitary group approach (UGA). It specially discusses how to construct symmetry functions adapted to the group chain U(5)>SO(5)>SO(3)>G. The functions are built up using the Lie algebraic technique and expressed in terms of Gelfand states of the (5) group.
1988, 4(06): 572-577
doi: 10.3866/PKU.WHXB19880603
Abstract:
In this paper the complex collection efficiency figures of n-InP in Fe~(8+)/Fe~(2+) solution are determined with light pulse technique by fast Fourier transformation using microcomputer. It is a half circle at fourth quadrant. According to theoratical model three photoelectrochemical kinetic parameters are calculated from the position of circle centre, the radius of circle and the characteristic frequency. Influences of the electrode potential and the light intensity on those parameters are dermined and the results are discussed.
In this paper the complex collection efficiency figures of n-InP in Fe~(8+)/Fe~(2+) solution are determined with light pulse technique by fast Fourier transformation using microcomputer. It is a half circle at fourth quadrant. According to theoratical model three photoelectrochemical kinetic parameters are calculated from the position of circle centre, the radius of circle and the characteristic frequency. Influences of the electrode potential and the light intensity on those parameters are dermined and the results are discussed.
1988, 4(06): 578-586
doi: 10.3866/PKU.WHXB19880604
Abstract:
FT-IR and Laser Raman spectra of (CH_3Cp)_2Fe have been measured. On the basis of qualitative assignment the force constants of Cp_2M(M=Mn,Fe,Ru) obtained by G-F matrix have been translated to the molecule of (CH_3Cp)_2Fe, only the metal coordinate force constants have been adjusted. The same method of G-F matrix has been used for calculating the vibrational spectra frequencies of (CH_3Cp)_2Fe, the result is consistent with the observal one.
FT-IR and Laser Raman spectra of (CH_3Cp)_2Fe have been measured. On the basis of qualitative assignment the force constants of Cp_2M(M=Mn,Fe,Ru) obtained by G-F matrix have been translated to the molecule of (CH_3Cp)_2Fe, only the metal coordinate force constants have been adjusted. The same method of G-F matrix has been used for calculating the vibrational spectra frequencies of (CH_3Cp)_2Fe, the result is consistent with the observal one.
1988, 4(06): 587-592
doi: 10.3866/PKU.WHXB19880605
Abstract:
This paper present a new method which diseribes colloidal particles model and calculation of any shape colloidal particles interaction enrgy in dispersed system. we choose a coordinate origin inside a convex body which represented a colloidal particle, take coordinates of direction θ and (φ)(0≤θ≤π, 0≤(φ)≤2π).For any direction (θ,(φ)), there is one and only one plane which is in cotact with the convex body and whose normal from the origin is in the direction (θ,(φ)). This plane is named the supporting plane in the direction (θ,φ). This plane is named the supporting plane in the direction (θ,φ). When a convex body A (or whose parallel body) moves around convex body B (or whose parallel body), assume interaction energy between two supporting planes of A and B can calculate from the DLVO theory, then interaction free energy of two any shape convex bodies is equal t surface inegral of interaction energy of the supporting planes over the whole surface of the convex body (or whose parallel body). A simple formula of interaction free energy of two identical spherical colloidal particles at constant surface potential has obained, namely,
V_(WJZ)=V_D·(1-(κη+α_1)/(β_1κa))
where V_(wjz) is our result, V_D is result of Derjaguin method, κ is Debye-Hükel parameter, a is radius of particle and ρ is the shortest distance between two identical spheres, α_1 and β_1 are a complex function of κρ. The α_1 and β_1 can determinate by way of power series method. we calculate interaction energy of two identical spherical particles use of values of α_1 and βin Table 2. Comparison of present result with those of ML, OCHW and computer result, when κa>10 it is better than result of ML, commensurates with result of OCHW.
This paper present a new method which diseribes colloidal particles model and calculation of any shape colloidal particles interaction enrgy in dispersed system. we choose a coordinate origin inside a convex body which represented a colloidal particle, take coordinates of direction θ and (φ)(0≤θ≤π, 0≤(φ)≤2π).For any direction (θ,(φ)), there is one and only one plane which is in cotact with the convex body and whose normal from the origin is in the direction (θ,(φ)). This plane is named the supporting plane in the direction (θ,φ). This plane is named the supporting plane in the direction (θ,φ). When a convex body A (or whose parallel body) moves around convex body B (or whose parallel body), assume interaction energy between two supporting planes of A and B can calculate from the DLVO theory, then interaction free energy of two any shape convex bodies is equal t surface inegral of interaction energy of the supporting planes over the whole surface of the convex body (or whose parallel body). A simple formula of interaction free energy of two identical spherical colloidal particles at constant surface potential has obained, namely,
V_(WJZ)=V_D·(1-(κη+α_1)/(β_1κa))
where V_(wjz) is our result, V_D is result of Derjaguin method, κ is Debye-Hükel parameter, a is radius of particle and ρ is the shortest distance between two identical spheres, α_1 and β_1 are a complex function of κρ. The α_1 and β_1 can determinate by way of power series method. we calculate interaction energy of two identical spherical particles use of values of α_1 and βin Table 2. Comparison of present result with those of ML, OCHW and computer result, when κa>10 it is better than result of ML, commensurates with result of OCHW.
1988, 4(06): 593-599
doi: 10.3866/PKU.WHXB19880606
Abstract:
The system for metal solvent extraction is a complicated one, which deals with electrolyte solution, non-electrolyte solution, phase equilibrium and chemical reaction simultaneously. It is interesting and important to establish an extraction thermodynamic model in hydrometaliutgy based on the modern theories of solution. In recent years the extraction thermodynamic model on one-metal system has been presented by authors[1-5].
The two-metal extraction system in which cobalt and copper, are co-extracted from sulfuric acid solution by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (EHEHPA) has been investigated in this paper.
The aqueous phase contains H_2SO_4, CoSO_4 and CuSO_4, mixed electrolytes with dissociation equilibrium. The activity coefficients for all ions are calculated by computer based on the Pitzer′s electrolyte theory with some assumptions and approximations made. The mean relative deviation between the experimental and calculated pH values is less than 0.02. The calculated results show that the simplified Pitzer′s equtions work very well for the aqueous phase with dissociation equilibrium.
Form the experimental equilibrium data in both phases and the activity coefficient of diluent determined by the gas-chromatography, the activity coefficients for HEHPA, Co(HR_2)_2, CU(HR_2)_2 and the thermodynamic extraction equilibrium constants K_(Co) and K_(Co) are obtained through “working reference state” proposed by the authors. The values of K_(Co) and K_(Co) keep constant respectively in the region of 0.6168-1.079 mol L~(-1) (the initial concentrations of extractant). Combining the improved Scatchard-Hildebrand theoretical model with the “working reference state”, the calculated values of activity coefficient for all components in the organic phase are obtained which are consistent with the experimental data. These results show that the “working reference state” is very useful for the two-metal extraction system and it seems to be possible to establish theoretical model for two-metal extraction equilibria in place of empirical ones.
The system for metal solvent extraction is a complicated one, which deals with electrolyte solution, non-electrolyte solution, phase equilibrium and chemical reaction simultaneously. It is interesting and important to establish an extraction thermodynamic model in hydrometaliutgy based on the modern theories of solution. In recent years the extraction thermodynamic model on one-metal system has been presented by authors[1-5].
The two-metal extraction system in which cobalt and copper, are co-extracted from sulfuric acid solution by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (EHEHPA) has been investigated in this paper.
The aqueous phase contains H_2SO_4, CoSO_4 and CuSO_4, mixed electrolytes with dissociation equilibrium. The activity coefficients for all ions are calculated by computer based on the Pitzer′s electrolyte theory with some assumptions and approximations made. The mean relative deviation between the experimental and calculated pH values is less than 0.02. The calculated results show that the simplified Pitzer′s equtions work very well for the aqueous phase with dissociation equilibrium.
Form the experimental equilibrium data in both phases and the activity coefficient of diluent determined by the gas-chromatography, the activity coefficients for HEHPA, Co(HR_2)_2, CU(HR_2)_2 and the thermodynamic extraction equilibrium constants K_(Co) and K_(Co) are obtained through “working reference state” proposed by the authors. The values of K_(Co) and K_(Co) keep constant respectively in the region of 0.6168-1.079 mol L~(-1) (the initial concentrations of extractant). Combining the improved Scatchard-Hildebrand theoretical model with the “working reference state”, the calculated values of activity coefficient for all components in the organic phase are obtained which are consistent with the experimental data. These results show that the “working reference state” is very useful for the two-metal extraction system and it seems to be possible to establish theoretical model for two-metal extraction equilibria in place of empirical ones.
1988, 4(06): 600-605
doi: 10.3866/PKU.WHXB19880607
Abstract:
By using the method of Discharge Flow-Resonance Fluorescence, the reaction of OH+SO_2+M was studied. The effect of wall reacton, diffusion and side reaction on the rate constants of the reaction was discussed. In the atmosphere of Ar or N_2, at 298K, the measured rate constants of the reaction were (1.5+0.32) × 10~(-31) cm~6 molec~(-2) s~(-1) and (3.6±0.79)×10~(-31)cm~6 melec~(-2) s~(-1), respectively.
By using the method of Discharge Flow-Resonance Fluorescence, the reaction of OH+SO_2+M was studied. The effect of wall reacton, diffusion and side reaction on the rate constants of the reaction was discussed. In the atmosphere of Ar or N_2, at 298K, the measured rate constants of the reaction were (1.5+0.32) × 10~(-31) cm~6 molec~(-2) s~(-1) and (3.6±0.79)×10~(-31)cm~6 melec~(-2) s~(-1), respectively.
1988, 4(06): 606-610
doi: 10.3866/PKU.WHXB19880608
Abstract:
The microtacticity of seven poly (n-alkyl methacrylates)prepared from radical polymerization has been determined by ~(13)C NMR. High syndiotactic stereoregularity was observed and the ester size showed little influence on the microtacticity of the chains. This phenomenon may be related to the structure of the terminal radical formed in the propagation reaction in free-radical polymerization. A preliminary explanation has been given.
The microtacticity of seven poly (n-alkyl methacrylates)prepared from radical polymerization has been determined by ~(13)C NMR. High syndiotactic stereoregularity was observed and the ester size showed little influence on the microtacticity of the chains. This phenomenon may be related to the structure of the terminal radical formed in the propagation reaction in free-radical polymerization. A preliminary explanation has been given.
1988, 4(06): 611-616
doi: 10.3866/PKU.WHXB19880609
Abstract:
From the reaction of Mo_2S_4(μ-dtp)(dtp)_3(H_2O) (I) (dtp = diethyldithiophosphanato) with 2,2'-bipyridine, the product Mo_3S_4(μ-dtp)(η~2-dtp)_2(η~1-dtp)(bpy)(Ⅱ) has been isolated, and characterized by X-ray crystallography. Crystal: (Ⅱ) belongs to triclinic system in space group Pi with crystallographic parameters as following., a=1.3638(3), b=1.3983(3), c=1.4699(2) nm, α=95.57°, β=91.87°, γ=117.40°; V=2.467(2) nm, Z=2, Dc=1.767 g.cm~(-3), final R=0.069, R_w= 0.076. The results of the structure determination show that the coordinated H_2O ligand and one of sulphur atoms of dtp on the Mo(3) atom of cluser(Ⅰ) have been substituted by 2,2′-bipyridine ligand. It has been pointed out that the ligand substitution reaction reported here is closely correlated with the existence of loosely-coordinated site in cluster (Ⅰ). In addition, the other types of substitution reactions of ligands are also discussed.
From the reaction of Mo_2S_4(μ-dtp)(dtp)_3(H_2O) (I) (dtp = diethyldithiophosphanato) with 2,2'-bipyridine, the product Mo_3S_4(μ-dtp)(η~2-dtp)_2(η~1-dtp)(bpy)(Ⅱ) has been isolated, and characterized by X-ray crystallography. Crystal: (Ⅱ) belongs to triclinic system in space group Pi with crystallographic parameters as following., a=1.3638(3), b=1.3983(3), c=1.4699(2) nm, α=95.57°, β=91.87°, γ=117.40°; V=2.467(2) nm, Z=2, Dc=1.767 g.cm~(-3), final R=0.069, R_w= 0.076. The results of the structure determination show that the coordinated H_2O ligand and one of sulphur atoms of dtp on the Mo(3) atom of cluser(Ⅰ) have been substituted by 2,2′-bipyridine ligand. It has been pointed out that the ligand substitution reaction reported here is closely correlated with the existence of loosely-coordinated site in cluster (Ⅰ). In addition, the other types of substitution reactions of ligands are also discussed.
1988, 4(06): 617-623
doi: 10.3866/PKU.WHXB19880610
Abstract:
Tracing out dehydrated reaction of β-hydroxy ester by FT-IR, luster Raman spectroscopy and EHMO calculation,it is found that the distribution for products, α,β-and, β, γ-unsaturated ester is dependent on super-conjugation of substitutedm ethyl on β-carbon. And it has been proved that the reaction examined is akinetic control.
Tracing out dehydrated reaction of β-hydroxy ester by FT-IR, luster Raman spectroscopy and EHMO calculation,it is found that the distribution for products, α,β-and, β, γ-unsaturated ester is dependent on super-conjugation of substitutedm ethyl on β-carbon. And it has been proved that the reaction examined is akinetic control.
1988, 4(06): 624-628
doi: 10.3866/PKU.WHXB19880611
Abstract:
The chemisorption of NH_3 on Ni(111) surface has been studied by X_a-DV method. Total energies, ground states, charges transfer and total densities of states are calculated for ontop and three-fold sites respectively, The results show that NH_3 tends to adsorb on on-top site and not to adsorb on three-fold site. The interaction between NH_3 and Ni(111)is mainly due to the mixture of the lone-pair orbital 3a_1 of NH_3 and the 4s orbital of Ni. Charge transfer from bonding orbitals to anti-bonding orbitals causes the activation of NH_3. The interaction between intermediate NH and Ni(111) surface inccluded in our calculations shows that the NH adsorbed on Ni(111) is much stronger than that of NH_3. So that the step NH_(ad)+2H_(ad)→NH_(3ad) needs much more energy on Ni(111) surface than that of on Fe surface. The difficulty of the NH_3 formation on Ni(111) surface is another possibel reason of why Ni is not a od catalyst for NH_3 synthese.
1988, 4(06): 629-635
doi: 10.3866/PKU.WHXB19880612
Abstract:
The interface adsorption and micelle formation of the mixed solution of fluorocarbon and hydrocarbon surfactants (7CFNa and C_8NBr, C_(10)NBr, C_(12)NBr mixtures) have been investigated. The surface tension and interfacial tension of the mixed solution have been determined by the drop-volume method (the ionic strengths of the solution are kept constant in 0.1 mol~(-1)L by adding NaBr).
By applying the Gibbs adsorption equation and using nonideal solution theory, the total adsorption amount and the individual adsorption amounts of each surfactant have been obtaioned. It has been shown that (I) at the surface the adsorption rules of various systems are essentially the same. At the heptane/water interface, the adsordtion rule of 7CFNa-C_3NBr system is similar to that at the surface, for 7CFNa-C_(10)NBr mixture the amount of satuated adsorption increases with increase in the molar ratio of any one surfactant from the 1:1 ratio at which the saturated adsorption amount is the least. However, the saturated adsorption amount for 7CFNa-C_(12)NBr system decreases with decrease in the mole ratio of 7CFNa in the mixture the adsorption rule is contrary to that at the surface; (2) The surfactant mixture has a very high interfacial activity. The efficiency of surface tension decreases and the effectiveness of surface tension increases with the increase in hydrocarbon chain length in cationic surfactants.
The interface adsorption and micelle formation of the mixed solution of fluorocarbon and hydrocarbon surfactants (7CFNa and C_8NBr, C_(10)NBr, C_(12)NBr mixtures) have been investigated. The surface tension and interfacial tension of the mixed solution have been determined by the drop-volume method (the ionic strengths of the solution are kept constant in 0.1 mol~(-1)L by adding NaBr).
By applying the Gibbs adsorption equation and using nonideal solution theory, the total adsorption amount and the individual adsorption amounts of each surfactant have been obtaioned. It has been shown that (I) at the surface the adsorption rules of various systems are essentially the same. At the heptane/water interface, the adsordtion rule of 7CFNa-C_3NBr system is similar to that at the surface, for 7CFNa-C_(10)NBr mixture the amount of satuated adsorption increases with increase in the molar ratio of any one surfactant from the 1:1 ratio at which the saturated adsorption amount is the least. However, the saturated adsorption amount for 7CFNa-C_(12)NBr system decreases with decrease in the mole ratio of 7CFNa in the mixture the adsorption rule is contrary to that at the surface; (2) The surfactant mixture has a very high interfacial activity. The efficiency of surface tension decreases and the effectiveness of surface tension increases with the increase in hydrocarbon chain length in cationic surfactants.
1988, 4(06): 636-640
doi: 10.3866/PKU.WHXB19880613
Abstract:
The conductivity and relaxation of the solutions of LiClO_4 in dimethyl siloxane-ethylene oxide copolymer (named DMS:EO:LiClO_4 for short) have been investigated systematically. The value of optimum of the conductivity is higher than 10~(-4)Scm~(-1) at room temperature at 0.394 mol L~(-1).
From comparison it was pointed that containing siloxane and the salts easy to be disoeiated in copolymer with PEO is helpful for promoting motion of ions.
The peparation and conductivity of the films obtained from the solution only by heat were also mentioned.
The conductivity and relaxation of the solutions of LiClO_4 in dimethyl siloxane-ethylene oxide copolymer (named DMS:EO:LiClO_4 for short) have been investigated systematically. The value of optimum of the conductivity is higher than 10~(-4)Scm~(-1) at room temperature at 0.394 mol L~(-1).
From comparison it was pointed that containing siloxane and the salts easy to be disoeiated in copolymer with PEO is helpful for promoting motion of ions.
The peparation and conductivity of the films obtained from the solution only by heat were also mentioned.
1988, 4(06): 641-644
doi: 10.3866/PKU.WHXB19880614
Abstract:
We derived a simplified formula of electrostatic energy for the two unlike spheres at constant surface potential using the rotation method, recently developed to calculate electrostatic energy of any shape particles. Surface integral of the mean curvature M_0=4π·2a_1a_2/(a_1+a_2), interaction energy of the supporting planes
V=εκ/4·{(ψ_1+ψ_2)~2(1-thκρ/2) - (ψ_1-ψ_2)~2(cthκρ/2-1)},
which is derived by HHF, where ε =delectric constant, κ =Debye-Hckel parameter, ψ_1 and ψ_2 =surface potential, ρ =shortest distance between dissimilar plates. Substituting M_0 and V into V_(WJZ)=∫Vd(s-2πρ~2), We obain
V_(WJZ)=(επa_1a_2)/(a_1+a_2){(ψ_1+ψ_2)~2ln[1+exp(-κρ)]×[1-(κρ+α_1)/(2β_1) (1/(κa_1)+1/(κa_2)]+(ψ_1-ψ_2)~2ln[1-exp(-κρ)]·[1-(κρ+α_2)/(2β_2)×(1/(κa_1)+1/(κa_2)]}
Numerical values of V_(WJZ) are compared with those of OCHW and BM, it approaches results of OCHW, However, when a_1/a_2>10 error of the rotation method increases.
We derived a simplified formula of electrostatic energy for the two unlike spheres at constant surface potential using the rotation method, recently developed to calculate electrostatic energy of any shape particles. Surface integral of the mean curvature M_0=4π·2a_1a_2/(a_1+a_2), interaction energy of the supporting planes
V=εκ/4·{(ψ_1+ψ_2)~2(1-thκρ/2) - (ψ_1-ψ_2)~2(cthκρ/2-1)},
which is derived by HHF, where ε =delectric constant, κ =Debye-Hckel parameter, ψ_1 and ψ_2 =surface potential, ρ =shortest distance between dissimilar plates. Substituting M_0 and V into V_(WJZ)=∫Vd(s-2πρ~2), We obain
V_(WJZ)=(επa_1a_2)/(a_1+a_2){(ψ_1+ψ_2)~2ln[1+exp(-κρ)]×[1-(κρ+α_1)/(2β_1) (1/(κa_1)+1/(κa_2)]+(ψ_1-ψ_2)~2ln[1-exp(-κρ)]·[1-(κρ+α_2)/(2β_2)×(1/(κa_1)+1/(κa_2)]}
Numerical values of V_(WJZ) are compared with those of OCHW and BM, it approaches results of OCHW, However, when a_1/a_2>10 error of the rotation method increases.
1988, 4(06): 645-648
doi: 10.3866/PKU.WHXB19880615
Abstract:
The vertical ionization potentials of B_2H_6 were calculated by means of the EOM/propagator method with a second-order approximation treatment. We used the 3-21G basis sets without adding polarization functions. The calculated ionization potentials are in od agreement with experimental values.
The vertical ionization potentials of B_2H_6 were calculated by means of the EOM/propagator method with a second-order approximation treatment. We used the 3-21G basis sets without adding polarization functions. The calculated ionization potentials are in od agreement with experimental values.
1988, 4(06): 649-652
doi: 10.3866/PKU.WHXB19880616
Abstract:
This paper reports the crystal and molecular structure of β-cyanoethyl-α-ferro cenylfluorobenzyl ether (C_5H_5FeC_5H_4CH(OCH_2CH_2CN)C_6H_4F). The title crystal belongs to the triclinic system and the space group is P1 with crystal parameters: a=0.7849(8) nm, b=1.1744(3) nm, c=1.9337(4) nm, α=74.99(1)°, β=87.28(5)°, γ=86.61(5)°, V=1.7176(2) nm, Z=4, D_c=1.405 g cm~(-3). The crystal was solved with direct method and fourier synthesis, refined with full matrix least-squares. The refinement eonveraged to R=0.043.
There are two molecules in an asymmetry unit. The geometrical features of the molecules and the characteristics of the molecular packing are discussed.
This paper reports the crystal and molecular structure of β-cyanoethyl-α-ferro cenylfluorobenzyl ether (C_5H_5FeC_5H_4CH(OCH_2CH_2CN)C_6H_4F). The title crystal belongs to the triclinic system and the space group is P1 with crystal parameters: a=0.7849(8) nm, b=1.1744(3) nm, c=1.9337(4) nm, α=74.99(1)°, β=87.28(5)°, γ=86.61(5)°, V=1.7176(2) nm, Z=4, D_c=1.405 g cm~(-3). The crystal was solved with direct method and fourier synthesis, refined with full matrix least-squares. The refinement eonveraged to R=0.043.
There are two molecules in an asymmetry unit. The geometrical features of the molecules and the characteristics of the molecular packing are discussed.
1988, 4(06): 653-656
doi: 10.3866/PKU.WHXB19880617
Abstract:
The variation of ehemiluminescent polarization for reaction Ba(~1S)+N_2O with respect to the Ba beam temperature or the average collision energy E_(rtr) was studied under the single collision condition on beam-gas apparatus. If E_(rtr)<0.06 eV, the distribution of rotational angular momentum for product BaO, i.e. -<P_2(J′·V_r)>, increased with the impact energy; while E_(rtr)>0.06 eV, -<P_2(J′·V_r)> decreased with the E_(rtr). It is plausible to point out the corresponding relationship between the characteristics of the reaction potential surface and the conformation of the intermediate complexes.
The variation of ehemiluminescent polarization for reaction Ba(~1S)+N_2O with respect to the Ba beam temperature or the average collision energy E_(rtr) was studied under the single collision condition on beam-gas apparatus. If E_(rtr)<0.06 eV, the distribution of rotational angular momentum for product BaO, i.e. -<P_2(J′·V_r)>, increased with the impact energy; while E_(rtr)>0.06 eV, -<P_2(J′·V_r)> decreased with the E_(rtr). It is plausible to point out the corresponding relationship between the characteristics of the reaction potential surface and the conformation of the intermediate complexes.
1988, 4(06): 657-659
doi: 10.3866/PKU.WHXB19880618
Abstract:
An autocatalytic reaction model X+2Y→3Y, Y+Z→2Z, Y→P, in a CSTR is put forward to model the phenomena of birhythum and tristability in isothermal, homogeneous chemical systems. Numerical simulations show that, under the proper values of the parameters, system may evolve to and remain at two or three different asymptotic states under same parameter's values but different initial values of X, Y and Z. In some cases, two of these asymptotic states are oscillatory, as shown in Fig.1. This is the phenomenon of birhythum. The stability of these asymptotic states are discussed. Some of them are not strickly stable but might be observed experimentally in chemical systems. It′s implications to the problem of biological evolution is also discussed.
An autocatalytic reaction model X+2Y→3Y, Y+Z→2Z, Y→P, in a CSTR is put forward to model the phenomena of birhythum and tristability in isothermal, homogeneous chemical systems. Numerical simulations show that, under the proper values of the parameters, system may evolve to and remain at two or three different asymptotic states under same parameter's values but different initial values of X, Y and Z. In some cases, two of these asymptotic states are oscillatory, as shown in Fig.1. This is the phenomenon of birhythum. The stability of these asymptotic states are discussed. Some of them are not strickly stable but might be observed experimentally in chemical systems. It′s implications to the problem of biological evolution is also discussed.
1988, 4(06): 660-664
doi: 10.3866/PKU.WHXB19880619
Abstract:
The reactions Ca(~1S_0)+ CH_2Cl_2, CHCl_3 and Ca(~3P)+ CH_2Cl_2, CHCl_3 were studied by means of the laser induced fluorescence (LIF). Systematic simulation of the observed LIF spectra revealed that change of the Ca atoms from the ~3p states to the ~1S_0 state brought about a decrease of the fraction of total energy ing to the ground state CaCl product vibration and an increase of the fraction of total energy ing to the ground state CaCl product rotation. Total cross sections for the reactions of Ca(~1S_0)+CH_(4-n)Cl_n(n=2, 3) and the fraction of the Ca atoms ing to the ~3P states in the discharge Ca beam were estimated from the LIF indensity of the CaCl product and total cross sections for the reactions Ca(~3P)+CH_(4-n)Cl_n. They are 0.39±2 nm, 0.45±2 nm, 1.8+0.1%, respectively.
The reactions Ca(~1S_0)+ CH_2Cl_2, CHCl_3 and Ca(~3P)+ CH_2Cl_2, CHCl_3 were studied by means of the laser induced fluorescence (LIF). Systematic simulation of the observed LIF spectra revealed that change of the Ca atoms from the ~3p states to the ~1S_0 state brought about a decrease of the fraction of total energy ing to the ground state CaCl product vibration and an increase of the fraction of total energy ing to the ground state CaCl product rotation. Total cross sections for the reactions of Ca(~1S_0)+CH_(4-n)Cl_n(n=2, 3) and the fraction of the Ca atoms ing to the ~3P states in the discharge Ca beam were estimated from the LIF indensity of the CaCl product and total cross sections for the reactions Ca(~3P)+CH_(4-n)Cl_n. They are 0.39±2 nm, 0.45±2 nm, 1.8+0.1%, respectively.
1988, 4(06): 665-668
doi: 10.3866/PKU.WHXB19880620
Abstract:
The internal state distributions of nascent CaCl formed in the reactions Ca + (1,1) and (1,2) C_2H_4Cl_2、(1,1,2) C_2H_2Cl_3, (1,1,2,2) C_2H_2Cl_4 have been studied by means of the laser induced fluorescence (LIF) in the beam-gas apparatus. The results showed that the vibrational distributions of the CaCl products from Ca+ (1, 1) C_2H_4Cl_2. (1,1,2,2) C_2H_2Cl_4 are similar to vibrational distributions of the CaCl products from Ca + CH_2Cl_2、CHCl_3, respectively. However, the vibrational distribution of the CaCl product from Ca+(1,1,2) C_2H_3Cl_3 is equivalent to the combination of that from Ca+(1,2) C_2H_4Cl_2 and Ca+(1,1,2,2) C_2H_2Cl_4. No LIF signal has been found in the reaction Ca+(1,1) C_2H_4Cl_2.
The internal state distributions of nascent CaCl formed in the reactions Ca + (1,1) and (1,2) C_2H_4Cl_2、(1,1,2) C_2H_2Cl_3, (1,1,2,2) C_2H_2Cl_4 have been studied by means of the laser induced fluorescence (LIF) in the beam-gas apparatus. The results showed that the vibrational distributions of the CaCl products from Ca+ (1, 1) C_2H_4Cl_2. (1,1,2,2) C_2H_2Cl_4 are similar to vibrational distributions of the CaCl products from Ca + CH_2Cl_2、CHCl_3, respectively. However, the vibrational distribution of the CaCl product from Ca+(1,1,2) C_2H_3Cl_3 is equivalent to the combination of that from Ca+(1,2) C_2H_4Cl_2 and Ca+(1,1,2,2) C_2H_2Cl_4. No LIF signal has been found in the reaction Ca+(1,1) C_2H_4Cl_2.
1988, 4(06): 669-672
doi: 10.3866/PKU.WHXB19880621
Abstract:
Multiphoton dissociation-ionization dynamics of Fe(CO)_5 were studied mass spectrometrically with a molecular beam and XeCl excimer laser. The results show that Fe(CO)_n~+ (n= 1,2,… ,5) and Fe_2(CO)_4~+ ions are formed mainly via ion-molecule reaction between Fe~+ and Fe(CO)_5 and dissociation following. A “ladder” model of Fe(CO)_5 photodissociation is presented in the paper.
Multiphoton dissociation-ionization dynamics of Fe(CO)_5 were studied mass spectrometrically with a molecular beam and XeCl excimer laser. The results show that Fe(CO)_n~+ (n= 1,2,… ,5) and Fe_2(CO)_4~+ ions are formed mainly via ion-molecule reaction between Fe~+ and Fe(CO)_5 and dissociation following. A “ladder” model of Fe(CO)_5 photodissociation is presented in the paper.
