2 Energy levels

In Table 1 we list the observed energies of the helium terms which enter into the present calculation of cross sections, our source being Martin's (1973) tabulation.

 

Table 1: Helium term energies in Ry. Observed: Martin (1973); theoretical: FC (frozen core), FCFH (frozen core Hartree Fock)

$\it i$	Term	Martin		FC	FCHF
1	$1\,^1{\rm S}$	0.000000		0.000000	0.000000
2	$2\,^3{\rm S}$	1.456717		1.396698	1.396522
3	$2\,^1{\rm S}$	1.515236		1.458400	1.458115
4	$2\,^3{\rm P}$	1.540783		1.482000	1.482374
5	$2\,^1{\rm P}$	1.559496		1.499698	1.500117
6	$3\,^3{\rm S}$	1.669780		1.607601	1.608044
7	$3\,^1{\rm S}$	1.684619		1.623498	1.623877
8	$3\,^3{\rm P}$	1.690993		1.629400	1.629850
9	$3\,^3{\rm D}$	1.695887		1.633501	1.633869
10	$3\,^1{\rm D}$	1.695916		1.633501	1.633921
11	$3\,^1{\rm P}$	1.696871		1.635104	1.635658
12	$4\,^3{\rm S}$	1.734128		1.671698	1.672261
13	$4\,^1{\rm S}$	1.739978		1.678005	1.678419
14	$4\,^3{\rm P}$	1.742499		1.680401	1.680772
15	$4\,^3{\rm D}$	1.744572		1.682098	1.682494
16	$4\,^1{\rm D}$	1.744594		1.682098	1.682524
17	$4\,^3{\rm F}$	1.744645		1.682098	1.682514
18	$4\,^1{\rm F}$	1.744645		1.682098	1.682514
19	$4\,^1{\rm P}$	1.745013		1.682804	1.683219
20	$5\,^3{\rm S}$	1.761910		1.699400	1.699848
21	$5\,^1{\rm S}$	1.764798		1.702604	1.702952
22	$5\,^3{\rm P}$	1.766048		1.703699	1.704116
23	$5\,^3{\rm D}$	1.767106		1.704603	1.705002
24	$5\,^1{\rm D}$	1.767121		1.704603	1.705019
25	$5\,^3{\rm F}$	1.767143		1.704603	1.705013
26	$5\,^1{\rm F}$	1.767143		1.704603	1.705013
27	$5\,^3{\rm G}$	1.767150		1.704603
28	$5\,^1{\rm G}$	1.767150		1.704603
29	$5\,^1{\rm P}$	1.767334		1.705000	1.705379
30	$6\,^3{\rm S}$	1.776389		1.714504	1.714299
31	$6\,^1{\rm S}$	1.778021		1.716701	1.716057
32	$6\,^3{\rm P}$	1.778734		1.717598	1.716714
33	$6\,^3{\rm D}$	1.779344		1.717003	1.717228
34	$6\,^1{\rm D}$	1.779351		1.717003	1.717239
35	$6\,^3{\rm F}$	1.779366		1.716804	1.717236
36	$6\,^1{\rm F}$	1.779366		1.716804	1.717236
37	$6\,^3{\rm G}$	1.779366		1.716804
38	$6\,^1{\rm G}$	1.779366		1.716804
39	$6\,^1{\rm P}$	1.779483		1.718598	1.717448

Table 1 also has the frozen-core (FC) theoretical energies used in our collision calculation. For comparison we show the frozen-core Hartree-Fock (FCHF) energies calculated by McEachran (1972); see also Cohen & McEachran (1967a,b) and McEachran & Cohen (1969) where some of these results and discussion of the method can be found.