Table 2. The various contributions to the magnetic susceptibility of δ-Pu.

${\mathrm{\chi }}_{\text{Neutron}}^{{\mathit{f}}^4+{\mathit{f}}^5}$ denotes the magnetic susceptibility associated with the magnetic 5f⁴ and 5f⁵ states of δ-Pu at room temperature as determined by our neutron spectroscopy measurements. ${\mathrm{\chi }}_{\mathrm{V}\mathrm{V}}^{{\mathit{f}}^6}$ gives the temperature-independent Van-Vleck contribution ${\mathrm{\chi }}_{\mathrm{V}\mathrm{V}}^{{\mathit{f}}^6}$ of the nonmagnetic 5f⁶ that is estimated from the published magnetic susceptibility of Am (see the text). The error bar for ${\mathrm{\chi }}_{\mathrm{V}\mathrm{V}}^{{\mathit{f}}^6}$ was estimated from the various values of the occupation of the 5f⁶ state of δ-Pu determined by different experiments (Table 1). The sum of both reproduces the static magnetic susceptibility χ_Bulk of δ-Pu as measured by magnetic susceptibility reasonably well (22). All quantities are given in units of 10⁻⁴ cm³/mol.

${\mathrm{\chi }}_{\text{Neutron}}^{{\mathit{f}}^4+{\mathit{f}}^5}$	${\mathrm{\chi }}_{\mathrm{V}\mathrm{V}}^{{\mathit{f}}^6}$	${\mathrm{\chi }}_{\text{Neutron}}^{{\mathit{f}}^4+{\mathit{f}}^5}+{\mathrm{\chi }}_{\mathrm{V}\mathrm{V}}^{{\mathit{f}}^6}$	χBulk
0.8(3)	3.1(15)	3.9(15)	5.3