Improved Virial Coefficients of⁴He from Dielectric Constant Measurements

Abstract

The expression for B(T) recently proposed by Aziz and Slaman for 4He allows a more precise and internally consistent analysis to be made of the dielectric constant data of Gugan and Michel, and this confirms that the new expression gives an excellent representation of the temperature dependent part of B(T) between 4,2 K and 27,2 K. Improved expressions for the third- and fourth-density virial coefficients C(T) and D(T) have also been obtained.

Macroscopic and microscopic polarizabilities of helium gas

“…The most accurate experimental determinations of gas permittivity appear to be those obtained by dielectric constant gas thermometry (DCGT) of 4 He. Gugan (1991) quotes, for example, an experimental value of A ε /R of 6221.31(16) × 10 −5 cm 3 K J −1 , obtained in the range 3-30 K. Another experimental value of A ε /R, 6221.11(3) × 10 −5 cm 3 K J −1 , obtained with DGCT over a similar temperature range was reported some years ago by Grohmann and Luther (1992).…”

“…Including the effects of relativity, as was done in the new calculations of Johnson and Cheng (1996), shifts the theoretical values further from the experimental results of Gugan (1991) and closer to those of Grohmann and Luther (1992). Taking instead the latter's experimental values leads to a new estimate of the Boltzmann constant, k = 1.380 628(16)×10 −23 J K −1 , provided one accepts the ab initio relativistic value of the atomic polarizability of Johnson and Cheng (1996) (section 3).…”

“…The uncertainty limits given here in the Boltzmann constant consist of 6 × 10 −6 , derived from the uncertainties quoted by Grohmann and Luther (1992) in their experimental value of A ε /R, plus 10 × 10 −6 derived from the uncertainty limits given by Johnson and Cheng (1996) for their theoretical value of α. The experimental uncertainties mainly derive from the various DCGT fits performed and the realization of an absolute temperature (such as the water triple point (Pavese and Molinar 1992)), as described by Gugan (1991). Gugan, for example, interpreted the discrepancy between his measured values of A ε /R and the earlier theoretical value (6221.061(3) × 10 −5 K J −1 ) of Weinhold (1982) as being due in part to an error in the reference temperature of up to −1.2 mK.…”

Polarizability of negatively charged helium‐like ions interacting with Coulomb and screened Coulomb potentials

“…[3,4] The dynamic dipole polarizability (DDP) of 1 Hand Psare studied by Kar et al [10] Few experimental results on the dipole polarizability of helium are also available in the literature. [32][33][34] Recent experimental investigation [35] on the tune-out wavelength (wavelength for which atomic polarizability approaches zero) of helium has opened up several possibilities for precise theoretical studies on the polarizability of two-electron systems.It is well-known that the two-electron negative ions, particularly, 1 H -, D -, T -, 1 H -, Pi -, Mu -, and Ps -, have very simple bound state spectra that contains only the one bound (ground), singlet state with total angular momentum, L 5 0, that is, 1 1 S state for short. The initial interest of 1 Hwas related to its astrophysical observations.…”

“…[3,4] The dynamic dipole polarizability (DDP) of 1 Hand Psare studied by Kar et al [10] Few experimental results on the dipole polarizability of helium are also available in the literature. [32][33][34] Recent experimental investigation [35] on the tune-out wavelength (wavelength for which atomic polarizability approaches zero) of helium has opened up several possibilities for precise theoretical studies on the polarizability of two-electron systems.…”