Table 1.

Exchange parameters (in meV) of the lowest χ² solutions of the ${\mathcal{H}}_{JK\mathrm{\Gamma }{\mathrm{\Gamma }}^{\prime }}$ model obtained for RPSO in this work by fitting inelastic neutron scattering data to linear spin wave theory

RPSO	J	K	Γ	${\mathrm{\Gamma }}^{\prime }$	χ2
Solution 1	0.32	−0.54	0.44	−0.12	67.7
Solution 2	0.23	−0.31	0.38	−0.08	68.9
Solution 3	0.16	−0.15	0.33	−0.04	69.7
Solution 4	0.25	−0.39	0.41	−0.08	69.7
Solution 5	0.37	−0.65	0.49	−0.14	70.5
Normalised	J	K	Γ	${\mathrm{\Gamma }}^{\prime }$	J3
RPSO	0.60 – 1.10	−1	0.75 − 2.20	−0.22 − −0.27	–
α-RuCl316,17,55	−0.30 −  −0.53	−1	0.41 − 0.85	0.22 − 0.52	0.25 − 0.50

For comparison, the range of  −K normalised exchange parameters reported for α-RuCl₃^16,17,55 have also been included.