Hydrogen–Deuterium Self-Exchange in Hydrogen Sulfide and Hydrogen Selenide as Studied with a Pulsed-Molecular-Beam Quadrupole Mass Filter

Abstract

Articles you may be interested inMolecular beam study of the mechanism of catalyzed hydrogen-deuterium exchange on platinum single crystal surfaces J. Chem. Phys. 62, 3149 (1975); 10.1063/1.430862Equilibrium constants of hydrogen-deuterium-tritium selfexchange reactions in water vapor as studied with a pulsed molecularbeam quadrupole mass filterThe equilibrium constants for hydrogen-deuterium self-exchange in hydrogen sulfide and hydrogen selenide have been studied over a wide range of deuterium atom percent using a pulsed-molecular-beam quadrupole mass filter. K HDS was found to be 3.88±0.03 at 24.0±0.4°C and KHDSe was found to be 3.92± 0.04 at 22± 1°C. The experimental results agree with calculations from spectroscopic data to within 1%. It is shown that equilibrium constants for self-exchange reactions in systems where two hydrogenic species are exchanged tend toward the geometric mean value of K = 4 in the series H;O: H,S: H 2 Se as expected from theory.

On the proper use of the Bigeleisen–Mayer equation and corrections to it in the calculation of isotopic fractionation equilibrium constants

“…Table 5 The comparison of equilibrium constant K calculated from this study and those from Wolfsberg et al (1970), Bron et al (1973), Richet et al (1977) and experiments. Wolfsberg et al (1970) and Bron et al (1973) Richet et al (1977 This study Experiments Friedman and Shiner(1966); (b) Pyper and Christensen (1975); (c) Pyper and Newbury (1970); (d) Richet et al (1977); (e) Bron et al (1973).…”

“…For the water vapor internal equilibrium reaction: H 2 O + D 2 O = 2HDO, large deviations were found between theoretical studies and experiments (Pyper et al, 1967;Pyper and Newbury, 1970;Pyper and Christensen, 1975). Wolfsberg (1969) showed that it was not sufficiently accurate to add anharmonic corrections without the contributions of G 0 terms to partition function ratios.…”

Hydrogen—deuterium exchange in water vapor: The mass spectrometric sensitivities and the equilibrium constant

“…Unfortunately, we cannot unambiguously confirm the theory on the basis of the present work. However, in previous tests of the theory using isotopic self-exchange reactions (NH3 [10], H2S [3,7], H2Se [3,7], and the tritiated water reactions [5]) the intensity ratios agreed with the theoretical squilibrium constant. It is hoped that this paper might stimulate others to devise a method to test the theory with more precision.…”

“…[5] but disagree with those in Refs. [1][2][3][4], (See Table 1 The iteration computer code also calculated the sensitivity ratio, S., at seven different times. The ratios are shown in Table 5.…”

“…[1][2][3][4] and recent theoretical calculations[6-3j of K » 3.85 at 25*C might be the result of a value of S different from unity. The meastEreaetU of the sensitivities of isotoplc species of water Is complicated by the phenomenon known as taenory effect.…”