Accurate potential energy curve for helium dimer retrieved from viscosity coefficient data at very low temperatures

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Main Authors: Costa, Éderson D'M., Lemes, Nelson H. T., Braga, João P.
Format: Preprint
Published: 2016
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author Costa, Éderson D'M.
Lemes, Nelson H. T.
Braga, João P.
author_facet Costa, Éderson D'M.
Lemes, Nelson H. T.
Braga, João P.
contents The long range potential of helium-helium interaction, which requires accurate 'ab initio' calculation, due to the small value of the potential depth, approximately 11 K (0.091 kJ/mol) at 2.96 angstrom, will be obtained in this study by an alternative technique. This work presents a robust and consistent procedure that provides the long range potential directly from experimental data. However, it is difficult to obtain experimental data containing information regarding such a small potential depth. Thereby, sensitivity analysis will be used to circumvent this difficulty, from which viscosity data at lower temperatures (<5K) were chosen as appropriate data to be used to retrieve the potential function between 3 and 4 angstrom. The linear relationship between the potential energy function and the viscosity coefficient will be established under quantum assumptions and the Bose-Einstein statistic. The use of quantum theory is essential, since the temperatures are below 5K. The potential obtained in this study describes the viscosity with an average error of 1.68% that is less than the experimental error (5%), with the results being similar to those obtained for recent 'ab initio' potentials.
format Preprint
id arxiv_https___arxiv_org_abs_1612_01195
institution arXiv
publishDate 2016
record_format arxiv
spellingShingle Accurate potential energy curve for helium dimer retrieved from viscosity coefficient data at very low temperatures
Costa, Éderson D'M.
Lemes, Nelson H. T.
Braga, João P.
Chemical Physics
Statistical Mechanics
The long range potential of helium-helium interaction, which requires accurate 'ab initio' calculation, due to the small value of the potential depth, approximately 11 K (0.091 kJ/mol) at 2.96 angstrom, will be obtained in this study by an alternative technique. This work presents a robust and consistent procedure that provides the long range potential directly from experimental data. However, it is difficult to obtain experimental data containing information regarding such a small potential depth. Thereby, sensitivity analysis will be used to circumvent this difficulty, from which viscosity data at lower temperatures (<5K) were chosen as appropriate data to be used to retrieve the potential function between 3 and 4 angstrom. The linear relationship between the potential energy function and the viscosity coefficient will be established under quantum assumptions and the Bose-Einstein statistic. The use of quantum theory is essential, since the temperatures are below 5K. The potential obtained in this study describes the viscosity with an average error of 1.68% that is less than the experimental error (5%), with the results being similar to those obtained for recent 'ab initio' potentials.
title Accurate potential energy curve for helium dimer retrieved from viscosity coefficient data at very low temperatures
topic Chemical Physics
Statistical Mechanics
url https://arxiv.org/abs/1612.01195