On obtaining interatomic potentials from multiproperty fits to experimental data

Abstract

High-resolution differential cross section (DCS) and accurate new limiting diffusion measurements for all the unlike-pair He+rare-gas systems are combined in constructing new multiproperty interatomic potentials. The new potentials predict most properties available for these systems, including independent high-resolution DCS measurements. Remaining discrepancies with earlier multiproperty potentials for HeKr and HeXe are attributed to incompatibilities among data sets used in the multiproperty fitting procedure. It is also shown that the 5% difference in well depths between two recently proposed potentials for HeXe is due to some of the data used in constructing these potentials, and that the DCS measurements of those studies are mutually consistent. Finally, the present potentials are refined slightly for agreement with high-energy cross section measurements. At the present level of reliability for DCS and dilute-gas data, it seems likely that high-resolution DCS and accurate (limiting) diffusion measurements will assist in determining He+molecule potentials. These two properties are particularly useful because they are independent of uncertainties in the corresponding molecule+molecule potentials.

Ab initio study of the lifetime of weakly bound He(21S)–Ne molecules

“…R 0 ¼ 5:0 a 0 , agree well with corresponding data from [6]: 15 cm À1 , 5:7 a 0 , 5:1 a 0 , respectively. The present calculation shows that the ground-state potential well supports one vibrational level with the dissociation energy D m ¼ 3:6 cm À1 ; see Figure 1, the thick long-dashed line.…”

Quasimolecular emission near the Xe(5p56s1,3P1– 5p6 1S0) and Kr (4p55s1,3P1– 4p6 1S0) resonance lines induced by collisions with He atoms

“…Previously, these potential curves have been already applied for the calculations of absorption spectra of Xe + He and Kr + He mixtures and the results obtained are in good agreement with the experimental data [4]. For the ground states the potential curves determined from the experimental data in [5] have been used.…”

Prediction of gaseous diffusion coefficients from thermal diffusion measurements and other experimental data

“…͑11͒ and the data at 300 K in Tables I and II. For comparison we have included in the tables corresponding reference values of D 12 0 from two sources: ͑i͒ average data calculated from the compilation of Mason and Marrero 18 and ͑ii͒ data computed from potential functions [19][20][21][22] which were recently reported in the literature. Inspection of the tables indicates that from 200 to 400 K the average deviation of the predicted from the experimental and potential values is only 0.5% and that, except for the system Ar-Kr, the agreement between the predicted ͑using experimental data at 300 K͒ and reference values is still very good up to 1000 K. The deviations for Ar-Kr are due to the fact that ␣ T 0 is not a constant as assumed in Eq.…”