Direct determination of long-range dipolar interactions in by neutron diffraction

¹ Istituto Nazionale per la Fisica della Materia, Unità di Genova v. Dodecaneso 33, I-16146 Genova, Italy
² Dipartimento di Fisica, Università di Genova v. Dodecaneso 33, I-16146 Genova, Italy
³ Istituto di Elettronica Quantistica, Consiglio Nazionale delle Ricerche v. Panciatichi 56/30, I-50127 Firenze, Italy
⁴ Istituto Nazionale per la Fisica della Materia, Unità di Firenze L.go E. Fermi 2, I-50125 Firenze, Italy
⁵ Dipartimento di Energetica “S. Stecco”, Università di Firenze v. di S. Marta 3, I-50139 Firenze, Italy
⁶ Dipartimento di Fisica, Università di Firenze L.go E. Fermi 2, I-50125 Firenze, Italy

Corresponding author: eguarini@tin.it

Received: 20 May 1999
Accepted: 1 November 1999

Abstract

Neutron diffraction experiments at low momentum transfer q offer the remarkable possibility to simultaneously measure the strength of the longest-range two- and three-body interactions in classical fluids, namely the London double-dipole and the Axilrod-Teller triple-dipole potentials, without need to resort to any model for the pair interaction. The results here reported of a new neutron diffraction study on the low-q structure of both gaseous and liquid Kr show that, by investigating a wide density range, a direct, i.e. model-independent, experimental determination of long-range forces can be performed.