Electrical conduction and diffusion studies in NH4H2PO4 and KH2PO4 single crystals

Electrical conduction (dc) studies are made with pure and cobalt(II)-doped single crystals of NH₄H₂PO₄ and KH₂PO₄. The effect of the dopant concentration on the enthalpy for the migration of protons and the enthalpy for the rotation of the H₂PO₄ group have been studied. It is suggested that proton migration occurs through a synchronous phosphate rotation mechanism. Tritium diffusion studies in KDP and ³²PO₄ diffusion in ADP crystals have been made. The mechanisms for the conduction and diffusion processes are found to be different in nature. The distribution coefficients of Co(II) dopant in ADP (2.92 × 10^?3) and KDP (1.14 × 10^?3) are calculated. The following enthalpy values are obtained.

     

2.

Transparent and anhydrous proton conductors based on PVA/imidazole/NH₄H₂PO₄ composites     

Hongting Pu  Mengdi Luo 《European Polymer Journal》2007,43(12):5076-5083

A new anhydrous proton conducting membrane for solid-state electrochromic device (ECD) based on poly(vinyl alcohol) (PVA), imidazole (Imi), and ammonium dihydrogen phosphate (NH₄H₂PO₄) was prepared. The structure of PVA/Imi/NH₄H₂PO₄ composite membrane was studied by X-ray diffraction and differential scanning calorimetry (DSC). The transmittance of the membrane always decreases with increasing content of the imidazolium. Compared with the PVA/NH₄H₂PO₄ membrane, the addition of proper amount of Imi can enhance the proton conductivity to a certain extent. At low PVA content, equal molar ratio of Imi and NH₄H₂PO₄ is favorable for high proton conductivity, while higher molar ratio of Imi and NH₄H₂PO₄ is beneficial at high PVA content.     

3.

Analysis of (NH₄)₂SO₄/(NH₄)H₂PO₄ mixtures by thermogravimetry and X-ray diffraction     

José Pérez  Eduardo Pérez  Beatriz del Vas  Luis García  Jose Luis Serrano 《Thermochimica Acta》2006,443(2):231-234

(NH₄)₂SO₄ and (NH₄)H₂PO₄ are the principal components in the powder material used in fire extinguishers. In this paper the mutual influence in their thermal decomposition is investigated by thermogravimetry. Two methods for the quantification of both salts in mixtures (NH₄)₂SO₄/(NH₄)H₂PO₄ are proposed. The first employs thermogravimetry and is based on the measurement of the mass fraction in the 500-550 °C interval, once (NH₄)₂SO₄ has totally decomposed to yield gaseous products. The second uses some selected peaks in the X-ray diffractogram.     

4.

NMR study of molecular reorientations in NH₄H₂AsO₄     

R. Grosescu 《Chemical physics letters》1973,21(1):80-82

Zeeman (T_1Z) and dipolar (T_1D) spin-lattice relaxation times of protons in NH₄H₂AsO₄ were measured as a function of temperature. The existence of a slow motion (τ ≈ 10^?3 see) is established, which is most probably a low frequency hindered reorientation of H₂AsO₄ groups. This motion is slowed down below the Curie point T_c. A sharp increase of the dipolar relaxation rate above T = 314°K indicates the possibility of a new high temperature phase transition in this compound.     

5.

Differential scanning calorimetry of RbH₂PO₄ and CsH₂PO₄     

B. Metcalfe  J.B. Clark 《Thermochimica Acta》1978,24(1):149-153

The high-temperature phase behaviour of RbH₂PO₄ and CsH₂PO₄ have been studied. RbH₂PO₄ undergoes a single quasi-irreversible phase transition with an enthalpy of 4.665 kJ mol^?1. The transition is found to occur over the temperature range 86–111°C. CsH₂PO₄ undergoes two transitions at 149 and 230°C. The lower one is quasi-irreversible and has an enthalpy of 4.284 kJ mol^?1. The one at 230°C is reversible and has an enthalpy of 1.071 kJ mol^?1.     

6.

DSC investigation of the thermal behaviour of (NH₄)₂SO₄, NH₄HSO₄ and NH₄NH₂SO₃     

Ilona Konkoly Thege 《Thermochimica Acta》1983,60(2):149-159

Gaseous products evolved from (NH₄)₂SO₄, NH₄HSO₄ and NH₄NH₂SO₃ during successive heating and cooling cycles were flushed with inert gas into analyzer Dräger tubes hooked tightly to the terminal port of the DSC cell base. This simple procedure allowed the starting temperature of the decomposition to be determined and the amount of the individual gases in the mixture to be identified and even estimated. NH₄NH₂SO₃ at 523 K in humid air produced HNH₂SO₃ initially and, on further cycling, (NH₄)₂SO₄ and NH₄HSO₄ also appeared. The ΔH_f values for NH₄HSO₄ were (kJ mole^?1): in an airtight sample holder 12.67, in a dry argon atmosphere 11.93, and in a static air atmosphere 10.92. Endothermic peaks for (NH₄)₂SO₄ and 498 and 411 K represented the incongruent melting point and the polymorphic transition of (NH₄)₂SO₄·NH₄HSO₄. After the first heating in air to 530 K, (NH₄)₂SO₄ and NH₄HSO₄ exhibited closely similar cyclic DSC curves. The endothermic peaks at about 393–420 K may be assigned to different combinations of (NH₄)₂SO₄ and NH₄HSO₄.     

7.

NH₄F/H₃PO₄体系中阳极氧化法制备TiO₂纳米管阵列     

李纲  刘中清  王磊  卢静  张昭 《无机化学学报》2009,25(6):1031-1037

以价廉的Ni板代替常用的Pt片为阴极,纯钛为阳极,采用电化学阳极氧化法在NH4F-H3PO4体系中制备出TiO2纳米管阵列.详细研究了制备参数(溶液酸度、氟离子浓度、外加电压和氧化时间)对所获纳米管阵列形貌的影响.采用场发射扫描电镜(FE-SEM)和X射线衍射(XRD)对样品的形貌和晶相结构进行了表征.在最优化的条件下,可以获得形貌规整、表面干净、有序的TiO2纳米管阵列.纳米管阵列的平均管径为60 nm.管长约530 nm.采用阳极氧化法制备的纳米管阵列是非晶态的.经400℃热处理2 h后,可以转变为锐钛矿相.实验结果还发现,经过热处理后,纳米管阵列变得更为有序,管径扩大至约95 nm.     

8.

NH₄PO₃-SiO₂复合电解质的溶胶凝胶法制备和导电性能          下载免费PDF全文

彭小波  陈西林  郑海波  程继贵  夏长荣 《无机化学学报》2007,23(9):1567-1571

用溶胶凝胶法制备了复合固体电解质xNH₄PO₃-SiO₂(x=1，2，4)，并研究了该电解质在125～250 ℃范围内的导电性能。复合电解质的相结构分析表明，NH₄PO₃和SiO₂在溶胶凝胶法制备过程中没有发生化学反应;复合电解质的电导率随着NH₄PO₃含量增大而提高，并与NH₄PO     

9.

Multiconfiguration self-consistent wavefunctions for CH₄, C₂H₄ and C₂H₆     

B. Levy 《Chemical physics letters》1973,18(1):59-62

The results of several MC SCF calculations on CH₄, C₂H₄ and C₂H₆ with minimun bases of Slater type AO's are reported. The computing method is a quadratically convergent process. Better final energies are obtained if localized MO's are used.     

10.

Thermal behaviour of two new salts of malonic acid: Cu(C₃H₂O₄)·4H₂O and Cu(NH₄)₂(C₃H₂O₄)₂     

F. Charbonnier 《Thermochimica Acta》1974,10(3):285-298

Two new salts of malonic acid have been prepared: the copper(II) malonate tetrahydrate and the copper(II)-ammonium double malonate. Their study by thermal analysis (TG and DTA) leads to the following results:Cu(C₃H₂O₄)·4H₂O: the dehydration is rather complex and it is only under careful conditions that an intermediate hydrate Cu(C₃H₂O₄)·3H₂O could be traced. At about 170°C the dehydration is not ended (the salt holds yet about 0.15H₂O) and the anhydrous salt occurs only at about 240°C. It decomposes immediately leading to residues the composition of which depends upon the surrounding atmosphere; the part played by the gas given off is discussed.Cu(NH₄)₂(C₃H₂O₄)₂: this salt melts and decomposes simultaneously at about 190°C. During the decomposition the copper nitride Cu₃N forms as intermediate compound (as well as copper metal). Concerning the final residues of the decomposition the results and the conclusions are the same as the ones of the previous case.     

11.

Infrared multiple-photon dissociation of N₂H₄ and CH₃NH₂ fluence dependence of the production of NH₂     

S.V. Filseth  J. Danon  D. Feldmann  J.D. Campbell  K.H. Welge 《Chemical physics letters》1979,63(3):615-620

The multiple-photon dissociation of N₂H₄ and CH₃NH₂ by pulsed CO₂ laser light to produce NH₂(X?²B_I has been studied using the laser-induced fluorescence detection method. The relative NH₂ yield, represented by the fluorescence signal, has been measured as a function of the fluence from the threshold at about 0.1 J/cm² to about 100 J/cm², at different CO₂-laser lines and at pressures down to 10^?4 Torr.     

12.

Thermal behaviour of (NH₄)₃VO₂F₄ and Na(NH₄)₂VO₂F₄     

B.R. Wani  U.R.K. Rao  K.S. Venkateswarlu  A.S. Gokhale 《Thermochimica Acta》1982,58(1):87-95

The thermal behaviour of (NH₄)₃VO₂F₄ and Na(NH₄)₂VO₂F₄ was investigated using TG, DTA and DSC techniques. The occurrence of a first order phase transition with the onset of decomposition in both the compounds is confirmed. The temperature, energetics and hysteresis of the transition are obtained. A possible path for the thermal degradation is given for both the compounds, and the residues are identified.     

13.

Die Trennung von Ar und O₂ sowie CH₄, C₂H₆, C₃H₈ und C₄H₁₀     

H. Hoffmann 《Fresenius' Journal of Analytical Chemistry》1968,233(6):432

Ohne Zusammenfassung     

14.

High-pressure phase relations of CsD₂PO₄     

A.I. Kingon  J.B. Clark  K. Gesi 《Journal of solid state chemistry》1981,38(3):307-311

The high-pressure phase diagram of CsD₂PO₄ to 4.5 GPa and temperatures between 0 and 470°C is reported. Comparisons are made with CsH₂PO₄ and correlated with the isotope effect on the high-temperature high-pressure phase relations of KH₂PO₄.     

15.

A re-interpretation of the crystal structure of ‘(NH₄)₂(NH₃)[Ni(NH₃)₂Cl₄]’ in terms of (NH₄)_2−2z[Ni(NH₃)₂]_z[Ni(NH₃)₂Cl₄]     

A. Leineweber 《Journal of solid state chemistry》2003,176(1):198-202

A re-interpretation and re-evaluation of single-crystal X-ray diffraction data of a previously reported ‘(NH₄)₂(NH₃)[Ni(NH₃)₂Cl₄]’ (J. Solid State Chem. 162 (2001) 254) give a new formula (NH₄)_2−2z[Ni(NH₃)₂]_z[Ni(NH₃)₂Cl₄] with z=0.152. This new formula results from defects in an idealized ‘(NH₄)₂[Ni(NH₃)₂Cl₄]’ basic structure, where two adjacent NH₄⁺ cations are replaced by one Ni(NH₃)₂²⁺ unit. Cl⁻ anions from the basic structure complete the coordination sphere of the new Ni²⁺ to [Ni(NH₃)₂Cl₄]²⁻.     

16.

Vapour-liquid equilibrium data for the systems C₂H₆ + N₂, C₂H₄ + N₂, C₃H₈ + N₂, and C₃H₆ + N₂     

Louis Grausø  Aage Fredenslund  Jørgen Mollerup 《Fluid Phase Equilibria》1977,1(1):13-26

High pressure vapour-liquid equilibrium data for the C₂H₆ + N₂, C₂H₄ + N₂, C₃H₈ + N₂, and C₃H₆ + N₂ systems are presented. The data are obtained isothermally in the range from 200 K to 290 K. For each point of data, temperature, pressure and liquid and vapour phase mole fractions are measured.Values for the vapour phase mole fractions are calculated from the obtained pressure, temperature and liquid phase mole fractions. The calculated values are compared with the experimental results, and it is found that the average mean deviation between calculated and experimental mole fractions is less than 0.009 for the systems considered in this work.     

17.

Phase relations of NH₄ClO₄ and NH₄BF₄ to high pressures     

P.W. RichterCarl W.F.T. Pistorius 《Journal of solid state chemistry》1971

The high pressure phase diagrams of NH₄ClO₄ and NH₄BF₄ were studied by means of differential thermal analysis and volumetric techniques. The high temperature portions of these diagrams are intermediate between those of the corresponding potassium and rubidium salts, but at low temperatures the onset of hydrogen bonding causes the appearance of phases which are unique to the ammonium compounds.     

18.

Surface-enhanced raman spectra of C₂H₂ and C₂H₄ adsorbed on silver colloid     

K. Manzel  W. Schulze  M. Moskvits 《Chemical physics letters》1982,85(2):183-186

We report the surface-enhanced Raman spectra of ethylene and acetylene adsorbed on colloidal silver particles formed by gas aggregation and isolated at low temperatures in solid adsorbate/argon matrices. The spectra of both molecules exhibit modes which are normally Raman-forbidden. Excitation with several visible laser frequencies indicated that the degree of enhancement increased towards the blue.     

19.

Kinetic isotope effects in the reaction H + C₂H₄ → C₂H₅     

Ko-Ichi Sugawara  Kiyoshi Okazaki  Shin Sato 《Chemical physics letters》1981,78(2):259-263

The high-pressure limiting rate constants of the reactions between H or D atoms and three isotopic ethylenes have been measured in the temperature range 206–461 K. Practically no isotope effects due to the differences between the ethylenes could be observed. This result does not agree with the prediction recently made by the activated complex theory.     

20.

Hydrothermal synthesis and characterization of a new organic templated metallophosphate [Zn(H₂PO₄)₂(HPO₄)][C₇H₁₇N₂]     

R. Kefi  C. Ben Nasr  F. Lefebvre  M. Rzaigui 《Polyhedron》2007

     

	KDP (eV)	ADP (eV)
Enthalpy for the migration of protons	0.01 ± 0.01	0.15 ± 0.02
Enthalpy for the rotation of phosphate group	0.71 ± 0.01	0.66 ± 0.01
Enthalpy for T-diffusion	0.14 ± 0.01	—
Enthalpy for 32PO4 diffusion	—	0.24 ± 0.01

Transparent and anhydrous proton conductors based on PVA/imidazole/NH4H2PO4 composites

A new anhydrous proton conducting membrane for solid-state electrochromic device (ECD) based on poly(vinyl alcohol) (PVA), imidazole (Imi), and ammonium dihydrogen phosphate (NH₄H₂PO₄) was prepared. The structure of PVA/Imi/NH₄H₂PO₄ composite membrane was studied by X-ray diffraction and differential scanning calorimetry (DSC). The transmittance of the membrane always decreases with increasing content of the imidazolium. Compared with the PVA/NH₄H₂PO₄ membrane, the addition of proper amount of Imi can enhance the proton conductivity to a certain extent. At low PVA content, equal molar ratio of Imi and NH₄H₂PO₄ is favorable for high proton conductivity, while higher molar ratio of Imi and NH₄H₂PO₄ is beneficial at high PVA content.     

Analysis of (NH4)2SO4/(NH4)H2PO4 mixtures by thermogravimetry and X-ray diffraction

(NH₄)₂SO₄ and (NH₄)H₂PO₄ are the principal components in the powder material used in fire extinguishers. In this paper the mutual influence in their thermal decomposition is investigated by thermogravimetry. Two methods for the quantification of both salts in mixtures (NH₄)₂SO₄/(NH₄)H₂PO₄ are proposed. The first employs thermogravimetry and is based on the measurement of the mass fraction in the 500-550 °C interval, once (NH₄)₂SO₄ has totally decomposed to yield gaseous products. The second uses some selected peaks in the X-ray diffractogram.     

NMR study of molecular reorientations in NH4H2AsO4

Zeeman (T_1Z) and dipolar (T_1D) spin-lattice relaxation times of protons in NH₄H₂AsO₄ were measured as a function of temperature. The existence of a slow motion (τ ≈ 10^?3 see) is established, which is most probably a low frequency hindered reorientation of H₂AsO₄ groups. This motion is slowed down below the Curie point T_c. A sharp increase of the dipolar relaxation rate above T = 314°K indicates the possibility of a new high temperature phase transition in this compound.     

Differential scanning calorimetry of RbH2PO4 and CsH2PO4

The high-temperature phase behaviour of RbH₂PO₄ and CsH₂PO₄ have been studied. RbH₂PO₄ undergoes a single quasi-irreversible phase transition with an enthalpy of 4.665 kJ mol^?1. The transition is found to occur over the temperature range 86–111°C. CsH₂PO₄ undergoes two transitions at 149 and 230°C. The lower one is quasi-irreversible and has an enthalpy of 4.284 kJ mol^?1. The one at 230°C is reversible and has an enthalpy of 1.071 kJ mol^?1.     

DSC investigation of the thermal behaviour of (NH4)2SO4, NH4HSO4 and NH4NH2SO3

Gaseous products evolved from (NH₄)₂SO₄, NH₄HSO₄ and NH₄NH₂SO₃ during successive heating and cooling cycles were flushed with inert gas into analyzer Dräger tubes hooked tightly to the terminal port of the DSC cell base. This simple procedure allowed the starting temperature of the decomposition to be determined and the amount of the individual gases in the mixture to be identified and even estimated. NH₄NH₂SO₃ at 523 K in humid air produced HNH₂SO₃ initially and, on further cycling, (NH₄)₂SO₄ and NH₄HSO₄ also appeared. The ΔH_f values for NH₄HSO₄ were (kJ mole^?1): in an airtight sample holder 12.67, in a dry argon atmosphere 11.93, and in a static air atmosphere 10.92. Endothermic peaks for (NH₄)₂SO₄ and 498 and 411 K represented the incongruent melting point and the polymorphic transition of (NH₄)₂SO₄·NH₄HSO₄. After the first heating in air to 530 K, (NH₄)₂SO₄ and NH₄HSO₄ exhibited closely similar cyclic DSC curves. The endothermic peaks at about 393–420 K may be assigned to different combinations of (NH₄)₂SO₄ and NH₄HSO₄.     

NH4F/H3PO4体系中阳极氧化法制备TiO2纳米管阵列

以价廉的Ni板代替常用的Pt片为阴极,纯钛为阳极,采用电化学阳极氧化法在NH4F-H3PO4体系中制备出TiO2纳米管阵列.详细研究了制备参数(溶液酸度、氟离子浓度、外加电压和氧化时间)对所获纳米管阵列形貌的影响.采用场发射扫描电镜(FE-SEM)和X射线衍射(XRD)对样品的形貌和晶相结构进行了表征.在最优化的条件下,可以获得形貌规整、表面干净、有序的TiO2纳米管阵列.纳米管阵列的平均管径为60 nm.管长约530 nm.采用阳极氧化法制备的纳米管阵列是非晶态的.经400℃热处理2 h后,可以转变为锐钛矿相.实验结果还发现,经过热处理后,纳米管阵列变得更为有序,管径扩大至约95 nm.     

NH4PO3-SiO2复合电解质的溶胶凝胶法制备和导电性能

用溶胶凝胶法制备了复合固体电解质xNH₄PO₃-SiO₂(x=1，2，4)，并研究了该电解质在125～250 ℃范围内的导电性能。复合电解质的相结构分析表明，NH₄PO₃和SiO₂在溶胶凝胶法制备过程中没有发生化学反应;复合电解质的电导率随着NH₄PO₃含量增大而提高，并与NH₄PO     

Multiconfiguration self-consistent wavefunctions for CH4, C2H4 and C2H6

The results of several MC SCF calculations on CH₄, C₂H₄ and C₂H₆ with minimun bases of Slater type AO's are reported. The computing method is a quadratically convergent process. Better final energies are obtained if localized MO's are used.     

Thermal behaviour of two new salts of malonic acid: Cu(C3H2O4)·4H2O and Cu(NH4)2(C3H2O4)2

Two new salts of malonic acid have been prepared: the copper(II) malonate tetrahydrate and the copper(II)-ammonium double malonate. Their study by thermal analysis (TG and DTA) leads to the following results:Cu(C₃H₂O₄)·4H₂O: the dehydration is rather complex and it is only under careful conditions that an intermediate hydrate Cu(C₃H₂O₄)·3H₂O could be traced. At about 170°C the dehydration is not ended (the salt holds yet about 0.15H₂O) and the anhydrous salt occurs only at about 240°C. It decomposes immediately leading to residues the composition of which depends upon the surrounding atmosphere; the part played by the gas given off is discussed.Cu(NH₄)₂(C₃H₂O₄)₂: this salt melts and decomposes simultaneously at about 190°C. During the decomposition the copper nitride Cu₃N forms as intermediate compound (as well as copper metal). Concerning the final residues of the decomposition the results and the conclusions are the same as the ones of the previous case.     

Infrared multiple-photon dissociation of N2H4 and CH3NH2 fluence dependence of the production of NH2

The multiple-photon dissociation of N₂H₄ and CH₃NH₂ by pulsed CO₂ laser light to produce NH₂(X?²B_I has been studied using the laser-induced fluorescence detection method. The relative NH₂ yield, represented by the fluorescence signal, has been measured as a function of the fluence from the threshold at about 0.1 J/cm² to about 100 J/cm², at different CO₂-laser lines and at pressures down to 10^?4 Torr.     

Thermal behaviour of (NH4)3VO2F4 and Na(NH4)2VO2F4

The thermal behaviour of (NH₄)₃VO₂F₄ and Na(NH₄)₂VO₂F₄ was investigated using TG, DTA and DSC techniques. The occurrence of a first order phase transition with the onset of decomposition in both the compounds is confirmed. The temperature, energetics and hysteresis of the transition are obtained. A possible path for the thermal degradation is given for both the compounds, and the residues are identified.     

Die Trennung von Ar und O2 sowie CH4, C2H6, C3H8 und C4H10

Ohne Zusammenfassung     

High-pressure phase relations of CsD2PO4

The high-pressure phase diagram of CsD₂PO₄ to 4.5 GPa and temperatures between 0 and 470°C is reported. Comparisons are made with CsH₂PO₄ and correlated with the isotope effect on the high-temperature high-pressure phase relations of KH₂PO₄.     

A re-interpretation of the crystal structure of ‘(NH4)2(NH3)[Ni(NH3)2Cl4]’ in terms of (NH4)2−2z[Ni(NH3)2]z[Ni(NH3)2Cl4]

A re-interpretation and re-evaluation of single-crystal X-ray diffraction data of a previously reported ‘(NH₄)₂(NH₃)[Ni(NH₃)₂Cl₄]’ (J. Solid State Chem. 162 (2001) 254) give a new formula (NH₄)_2−2z[Ni(NH₃)₂]_z[Ni(NH₃)₂Cl₄] with z=0.152. This new formula results from defects in an idealized ‘(NH₄)₂[Ni(NH₃)₂Cl₄]’ basic structure, where two adjacent NH₄⁺ cations are replaced by one Ni(NH₃)₂²⁺ unit. Cl⁻ anions from the basic structure complete the coordination sphere of the new Ni²⁺ to [Ni(NH₃)₂Cl₄]²⁻.     

Vapour-liquid equilibrium data for the systems C2H6 + N2, C2H4 + N2, C3H8 + N2, and C3H6 + N2

High pressure vapour-liquid equilibrium data for the C₂H₆ + N₂, C₂H₄ + N₂, C₃H₈ + N₂, and C₃H₆ + N₂ systems are presented. The data are obtained isothermally in the range from 200 K to 290 K. For each point of data, temperature, pressure and liquid and vapour phase mole fractions are measured.Values for the vapour phase mole fractions are calculated from the obtained pressure, temperature and liquid phase mole fractions. The calculated values are compared with the experimental results, and it is found that the average mean deviation between calculated and experimental mole fractions is less than 0.009 for the systems considered in this work.     

Phase relations of NH4ClO4 and NH4BF4 to high pressures

The high pressure phase diagrams of NH₄ClO₄ and NH₄BF₄ were studied by means of differential thermal analysis and volumetric techniques. The high temperature portions of these diagrams are intermediate between those of the corresponding potassium and rubidium salts, but at low temperatures the onset of hydrogen bonding causes the appearance of phases which are unique to the ammonium compounds.     

Surface-enhanced raman spectra of C2H2 and C2H4 adsorbed on silver colloid

We report the surface-enhanced Raman spectra of ethylene and acetylene adsorbed on colloidal silver particles formed by gas aggregation and isolated at low temperatures in solid adsorbate/argon matrices. The spectra of both molecules exhibit modes which are normally Raman-forbidden. Excitation with several visible laser frequencies indicated that the degree of enhancement increased towards the blue.     

Kinetic isotope effects in the reaction H + C2H4 → C2H5

The high-pressure limiting rate constants of the reactions between H or D atoms and three isotopic ethylenes have been measured in the temperature range 206–461 K. Practically no isotope effects due to the differences between the ethylenes could be observed. This result does not agree with the prediction recently made by the activated complex theory.