Dihelium

• Formula: He₂
• Molecular weight: 8.005204
• IUPAC Standard InChI:
  

  InChI=1S/He2/c1-2 Download the identifier in a file.

• IUPAC Standard InChIKey: GHVQTHCLRQIINU-UHFFFAOYSA-N
• CAS Registry Number: 12184-98-4
• Chemical structure:
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Constants of diatomic molecules

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Klaus P. Huber and Gerhard H. Herzberg

Data collected through November, 1976

Diatomic constants for ⁴He₂

State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
Rydberg	Rydberg series of np 3g levels (b,e,i,l,p,r,s,t,u,...)
	1 = 34302.20 - R/n=0.071)2, n=2...17
	↳Ginter and Ginter, 1968; Rosen, 1970
	Rydberg series of np 3g+ levels (c,g,k',n,p',r',s',t',...)
	1 = 34302.20 - R/n=0.777)2, n=3...12
	↳Ginter and Ginter, 1968; Rosen, 1970
u 3g 10p	177291	[1628.69] 2Z	(35.25)		7.212 2	0.222 2		[0.000503] 2		1.081	u a R	33189.16 Z
	↳Ginter and Ginter, 1968
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
t' 3g+ 10p	[177969]				[8.27] 3						t' a V	33026.6 Z
	↳Ginter and Ginter, 1968
t 3g 9p	177027	[1629.15] 4 Z	(35.25)		7.212 4	0.230 4		[0.000507] 4		1.081	t a R	32925.96 Z
	↳Ginter and Ginter, 1968
s' 3g+ 9p	[177636]				[8.04] 3						s' a V	32693.2 Z
	↳Ginter and Ginter, 1968
s 3g 8p	176658	[1629.30] 5 Z	(35.25)		7.213 5	0.2234 5		0.00051 5		1.0806	s a R	32556.66 Z
	↳Ginter and Ginter, 1968
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
r' 3g+ 8p	[177154]				[7.78] 3						r' a V	32211.7 Z
	↳Ginter and Ginter, 1968
r 3g 7p	176117	(1700.56) 6	(35.25)		[7.1044] 6	6		[0.000508] 6		[1.0889]	r d R	11625.3 Z
	↳Rosen, 1970
	176117										r a R	32016.56 Z
	↳Ginter and Ginter, 1968
p' 3g+ 7p	[176421]				[7.543] 3						p' a	31478.6 Z
	↳Ginter and Ginter, 1968
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
q 3u 6d	[176195]				[7.092] 7			[0.00050] 7		[1.0898]	q c V	20365
	↳Dieke, 1929; Rosen, 1970
											q b V	26483
	↳Dieke, 1929; Rosen, 1970
q 3u 6d	[(176169)]										q c R	(20330)
	↳Dieke, 1929; Rosen, 1970
											q b R	(26466)
	↳Dieke, 1929; Rosen, 1970
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
q 3u+ 6d	[176120]							[] 7			q c R	20288
	↳Dieke, 1929; Rosen, 1970
											q b R	26409
p 3g 6p	175281	1701.18 Z	35.35		7.220 8	0.224		0.000514		1.0801	p d R	10788.68 Z
	↳Rosen, 1970
	175281										p a R	31179.93 Z
	↳Ginter and Ginter, 1968
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
o 3u+ 6s	[176001]				[7.109]			[0.00051]		[1.0885]	o c V	20168.8 Z
	↳missing citation
	[176001]										o b R	26290.3 Z
	↳Dieke, Imanishi, et al., 1929; Rosen, 1970
n 3g+ 6p	174389	[1619.52] Z	(36.5)		7.4754 9	0.2490		[0.000721] 10		1.0615	n a	30283.26 Z
	↳Jevons, 1932; Orth and Ginter, 1976
m 3u 5d	[174863]				[7.09] 11					[1.091]	m c V	(19039)
	↳Rosen, 1970
											m b V	(25152)
	↳Rosen, 1970
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
m 3u 5d	174778				[7.07] 12						m c R	(18944)
	↳Rosen, 1970
											m b R	(25070)
	↳Rosen, 1970
m 3u+ 5d	[174730]										m c R	18899
	↳Rosen, 1970
											m b R	25019
	↳Rosen, 1970
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
l 3g 5p	173884	[1633.96] 13 Z	(35.25)		7.226 13	0.222 13		[0.000512] 13		1.0797	l d R	9393.9 Z
	↳Rosen, 1970
												29785.31 Z
	↳Ginter and Ginter, 1968
k 3u+ 5s	(173698)	[1635.3] Z			7.232	0.23				1.079	k c V	18683.5 Z
	↳Rosen, 1970
											k b R	24804.8 Z
	↳Rosen, 1970
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
k' 3g+ 5p	172236	1686.90 Z	38.10		7.379 14	0.349 15		[5.8E-4]		1.0684	k' a R	28127.58 Z
	↳Orth and Ginter, 1976
j 3u 4d	171573	1702.24 16Z	35.07		7.2088 16	0.2248 17		5.2E-4 16		1.0810	j c V	16583.18 16Z
	↳Brown and Ginter, 1973
											j b V	22704.5 16Z
	↳Brown and Ginter, 1973
j 3u 4d	171402	1680.94 16 Z	40.81		7.1860 16	0.2296 18		5.4E-4 16		1.0827	j c R	16400.69 16 Z
	↳Brown and Ginter, 1973
											j b R	22522.0 16 Z
	↳Brown and Ginter, 1973
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
j 3u+ 4d	171323	1669.79 19	39.09								j c R	16316.54 19 Z
	↳Brown and Ginter, 1973
j 3u+ 4d 20											j b R	22437.8 19 Z
	↳Brown and Ginter, 1973
i 3g 4p	171290	[1637.94] 21Z	(35.25)		7.242 21	0.223 21		[5.14E-4] 21		1.0785	i a R	27193.01 Z
	↳Ginter and Ginter, 1968; Rosen, 1970
h 3u+ 4s	(170884)	[1637.9] Z			7.264 22	0.23		(5.24E-4)		1.077	h c V	15870.7 Z
	↳Dieke, Imanishi, et al., 1929; Rosen, 1970; Brown and Ginter, 1973
											h b R	21992.2 Z
	↳Dieke, Imanishi, et al., 1929; Rosen, 1970; missing citation
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
g 3g+ 4p	167714	[1589.92] Z	(41)		7.2207	0.2478		[5.38E-4] 23		1.0801	g a R	23597.00 Z
	↳Orth and Ginter, 1976
f 3u 3d	166303	1706.82 Z	35.10		7.230 24	0.227 25		[5.26e-4] 26		1.0794	f c V	11316.06 Z
											f b V	17437.3 Z
	↳missing citation
f 3u 3d	165877 27	1661.48 Z	44.79		7.136 24	0.235 28		[5.34E-4] 29		1.0865	f c	10864.53 Z
	↳Ginter, 1966
											f b	16985.8 Z
	↳Ginter, 1965; Rosen, 1970
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
f 3u+ 3d	165685	1635.77 Z	44.41		7.071 24	0.246 30		[5.31E-4] 31		1.0914	f c R	10659.33 Z
											f b R	106780.6 Z
e 3g 3p	165598	1721.22 Z	34.970 32		7.2838 33	0.2215 34		5.22E-4		1.0754	ea 35 R	21507.26 Z
	↳Brown and Ginter, 1971
d 3u+ 3p	164479	1728.01 Z	36.13 36		7.342	0.2244 37		5.32E-4		1.0712	d c V	9502.7 Z
	↳Ginter, 1965
											d b R V	15623.1 Z
	↳missing citation
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
c 3g+ 3p	155053	1583.85 Z	52.74 38		7.0048	0.3105 39		[5.56E-4] 40		1.0966	c a R	10889.48 Z
	↳Ginter, 1965, 2
b 3g 2p	148835	1769.07 Z	35.02 41		7.4473 42	0.2196 43		[5.30E-4] 44		1.0635	b a R	4768.2 Z
	↳Hepner and Herman, 1956; Gloersen and Dieke, 1965
a 3u+ 2s	144048	1808.56 Z	38.21 45 46		7.7036 47	0.2281 48		5.56E-4 49		1.0457	(a X)	144935 50
S 1g 8p	[177515]				(7.21)	(0.22)				(1.081)	S A R	30228.6 Z
	↳Rosen, 1970
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
R 1g 7p	[176983]				(7.22)	(0.22)				(1.080)	R A R	29696.4 Z
	↳Rosen, 1970
P 1g 6p	[176160]				(7.22)	(0.22)				(1.080)	P A R	28873.9 Z
	↳Rosen, 1970
M 1u 5d	[(174838)]				[7.09] 51					[1.091]	M B	(24050)
	↳Rosen, 1970
M 1u 5d	[(174788)]				[7.07] 52					1.091	M B	(24000)
	↳Rosen, 1970
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
M 1u+ 5d					[7.07] 52					1.091	M B	(23960)
	↳Rosen, 1970
L 1g 5p	[174794]				(7.23)	(0.222)				(1.079)	L A R	27507.8 Z
	↳Rosen, 1970
J 1u 4d	[172416]				[7.097] 53			[5.0E-4]		[1.0894]	J C V	14183.90 53 Z
	↳Brown and Ginter, 1973
											J B V	21627.9 53 Z
	↳Brown and Ginter, 1973
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
J 1u 4d	[172290]				[7.080] 53			[5.4E-4]		[1.0908]	J C	14058.37 53 Z
	↳Brown and Ginter, 1973
											J B	21502.4 53 Z
	↳Brown and Ginter, 1973
J 1u+ 4d	[172222] 54										J C R	13990.32 54 Z
	↳Brown and Ginter, 1973
J 1u+ 4d 55											J B R	21434.3 54 Z
	↳Brown and Ginter, 1973
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
I 1g 4p	[172266]				(7.242)	(0.223)				(1.078)	I A R	24979.6 Z
	↳Rosen, 1970
H 1u+ 4s	[171951]				(7.26) 56	(0.23)				(1.077)	H C V	13719.5 Z
	↳Rosen, 1970; Brown and Ginter, 1973
											H B R	21163.5 Z
	↳Rosen, 1970; Brown and Ginter, 1973
F 1u 3d	166304	1706.59 Z	35.06		7.230 57	0.225 58		[5.20E-4] 59		1.0794	F B V	16360.9 Z
	↳Ginter, 1965, 3; Ginter, 1966
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
F 1u 3d	165971 60	1670.87 Z	20.03		7.156 57	0.235		[5.24E-4] 61		1.0849	F B	16008.3 Z
	↳Ginter, 1965, 3; Ginter, 1966
F 1u+ 3d	(165813)	[1564.25] Z	(10)		7.098 57	0.246		[5.21E-4] 62		1.0894	F B R	15837.5 Z
	↳Ginter, 1965, 3; Ginter, 1966
E 1g 3p	165911	1721.19 Z	34.76 63		7.2705 64	0.2156 65		5.20E-4		1.0764	E A R	19476.61 Z
	↳Brown and Ginter, 1971
D 1u+ 3s	165085	1746.43 Z	35.54		7.365	0.2180 66		5.24E-4 67		1.0694	D B 68 R V	15161.81 Z
	↳Ginter, 1965, 3
											D X 69 70
State	Te	e	exe	eye	Be	e	e	De	e	re	Trans.	00
C 1g+ 3p	157415	1653.43 Z	41.04 71		7.052	0.215 72		5.08E-4 73		1.0929	C A R	10945.50 Z
	↳Ginter, 1965, 2; Rosen, 1970
B 1g 2p	149914	1765.76 Z	34.39 74		7.403 75	0.216 75		5.02E-4 75		1.0667	(B-A)	3501.5 76
A 1u+ 2s	146365 77	1861.33 Z	35.28 78		7.7789	0.2166 79		5.44E-4		1.0406	AX 80	147279 81
	↳Tanaka and Yoshino, 1963; Mies and Smith, 1966; Smith, 1967; Chow, Smith, et al., 1971
X 1g+	0 82									2.97 83

Notes

1	missing note
2	Refers to -. B0(3+) ~ 5.6, strongly affected by l-uncoupling.
3	Effective value, strongly affected by l-uncoupling.
4	Refers to -. B0(3+) = 5.87, strongly affected by l-uncoupling.
5	Refers to -. B0(3+) = 6.13, strongly affected by l-uncoupling.
6	Constants refer to -; B0(3+)= 6.375 affected by l-uncoupling. v=1 is perturbed; approximate deperturbed constants for -: B1 = 6.886, G(1/2) = 1629.7.
7	Strong l-uncoupling. The rotational constants Dieke, 1929 refer to the average of - and -.
8	Refers to -. B0(3+) = 6.630 affected by l-uncoupling.
9	Several small accidental perturbations.
10	D1 = 6.82E-4, H0 = 14.2E-8, H1 ~ -26E-8.
11	Average of - and - as given by Rosen, 1970.
12	Average of +, +, + as given by Rosen, 1970.
13	Refers to -.
14	Several small accidental perturbations.
15	missing note
16	The vibrational and rotational constants refer to - and - which are less affected by l-uncoupling.
17	missing note
18	missing note
19	Constants refer to N'=1.
20	Strongly perturbed by l-uncoupling and by interaction with the h state. 22
21	Constants refer to 3-.
22	Brown and Ginter, 1973 give average effective constants for the four interacting components j(3u+, 3u+, 3u+) and h 3u+.
23	H0 = 2.0E-8.
24	These constants are corrected for l-uncoupling effects.
25	missing note
26	D1=5.28E-4, D2=5.50E-4, H0=2.5E-8
27	Ab initio calculations of f 3u and F 1u Browne, 1965, Gupta and Matsen, 1969 yield excellent agreement with the observed constants and confirm the presence of substantial potential maxima; see also Mulliken, 1964.
28	missing note
29	D1=5.34E-4, D2=5.74E=4, H0=2.9E-8.
30	missing note
31	D1=5.34E-4, D2=5.45E-4, H0 = 0.91E-8.
32	See also 33
33	The rotational constants refer to - Brown and Ginter, 1971; B(3-)-B(3+) ~ +0.072. Slightly different constants were given by Dieke and Robinson, 1950 who also derived constants for 3He2.
34	missing note
35	Observed in absorption in a pulsed discharge Callear and Hedges, 1967.
36	missing note
37	missing note
38	eze = -0.4875.
39	v= 0.1629(v+1/2)2 - 0.0655(v+1/2)3.
40	D1= 5.76E-4, D2= 6.11E-4,...; H0=1.32E-8, H1= -0.40E-8, H2=-5.3E-8,... .
41	missing note
42	The constants refer to 3- and were derived by Ginter, 1965 from the d, fb bands; B(3-) - B(3+) ~ +0.026 Ginter, 1965. The triplet splitting is partially resolved in the db bands Ginter, 1965.
43	missing note
44	D1= 5.34E-4,...; H0= 2.80E-8, H1= 3.60E-8,...
45	Brown and Ginter, 1971
46	There is good experimental Ludlum, Larson, et al., 1967, Ginter and Battino, 1970 and theoretical Poshusta and Matsen, 1963, Klein, Greenawalt, et al., 1967, Gupta, 1972 evidence for a potential maximum in this state. Ludlum, Larson, et al., 1967 place the maximum at 0.067 eV above the asymptote; the net dissociation energy is 1.850 eV.
47	From molecular beam magnetic resonance experiments Lichten, McCusker, et al., 1974, Vierima, 1975 have determined the triplet splitting for N=1 and 3. The splitting constants (extrapolated to N=0) are = -0.03666 Lichten, McCusker, et al., 1974, Vierima, 1975, = -0.0000808 cm-1 Lichten, McCusker, et al., 1974, Vierima, 1975. An ab initio calculation gives = -0.04089 Beck, Nicolaides, et al., 1974.
48	missing note
49	He ~ 2.7E-8 Brown and Ginter, 1971.
50	Energy of a 3u+,v=0,N=0 above He(1S) + He(1S), based on D00(He2+)= l9073 cm-1. See also 81
51	Average of - and - as given by Rosen, 1970.
52	Average of +, +, + as given by Rosen, 1970.
53	These constants refer to - and - which are less affected by l-uncoupling.
54	Refers to N=1.
55	Strongly perturbed by l-uncoupling and interaction with H 1u+. 56
56	Brown and Ginter, 1973 give average effective constants for the four interacting components J(1u+, 1u+, 1u+) and H 1u+.
57	These constants are corrected for l-uncoupling effects.
58	missing note
59	D1=5.26E-4, H0=2.18E-8.
60	Ab initio calculations of f 3u and F 1u Browne, 1965, Gupta and Matsen, 1969 yield excellent agreement with the observed constants and confirm the presence of substantial potential maxima; see also Mulliken, 1964.
61	D1=5.26E-4, H0 = 1.97E-8.
62	D1=5.29E-4.
63	missing note
64	The rotational constants refer to - Brown and Ginter, 1971; B(-)-B(+) ~ + 0.044.
65	missing note
66	missing note
67	missing note
68	Franck-Condon factors Zhirnov and Shadrin, 1968.
69	The weak maximum near 676 Å in the Hopfield continuum is ascribed by Chow and Smith, 1971 to the transition DX.
70	continuum
71	eze= -0.1315. Calculations of Guberman and Goddard, 1972 give a potential hump of 0.22 eV at 2.09 Å; see also Andresen and Kuppermann, 1975 and Guberman and Goddard, 1975.
72	missing note
73	H0 = 1.72E-8,...
74	Ginter, 1965, 3.
75	Be refers to -; B(-)-B(+) = +0.019; e = -0.0015 Ginter, 1965, 3, e = +0.05E-4 Ginter, 1965, 3.
76	From Rosen, 1970.
77	RKR potential curve Smith and Chow, 1970[see also Rosen, 1970]; ab initio potential Mukamel and Kaldor, 1971. The latter gives vibrational and rotational levels in good agreement with the experimental values. Tanaka and Yoshino, 1963 have established, from the absorption and emission bands near 600 Å, a potential maximum of 0.059 eV in the A 1u+ state. Theoretical work by Allison, Browne, et al., 1966, Scott, Greenawalt, et al., 1966, Guberman and Goddard, 1972 gives maxima of 0.084,0.153,0.061 eV, respectively; see also Andresen and Kuppermann, 1975, Guberman and Goddard, 1975.
78	Brown and Ginter, 1971
79	Brown and Ginter, 1971.
80	Transitions from the low vibrational levels of A 1u+ to X 1g+ gives rise to the Hopfield continuum; see MOLSPEC. 1, 404. Transitions from the high vibrational levels as well as the continuous range of energy levels of A 1u+ to X 1g+ give rise to diffuse bands near 600 Å observed in emission Mies and Smith, 1966, Smith, 1967 and absorption Tanaka and Yoshino, 1963, Chow, Smith, et al., 1971 with quite different intensity distribution. See also Tanaka, Jursa, et al., 1958, Chow and Smith, 1971 and Michaelson and Smith, 1970, Mukamel and Kaldor, 1973, Peatman and Wu, 1973. Observed absorption coefficients near 600 Å Chow, Smith, et al., 1971 agree fairly well with those predicted by Sando and Dalgarno, 1971.
81	Energy of the v=0,N=0 level of A 1u+ relative to He(1S) + He(1S), calculated from the corresponding value for a 3u+ by adding the energy difference v = 2343.91 ± 0.05 cm-1 Miller, Freund, et al., 1975 as determined by Miller, Freund, et al., 1975 from singlet-triplet anticrossings. Optical measurements give v = 2344.1 cm-1 Ginter and Battino, 1970. The relative position of the levels is much more accurately known than their absolute values.
82	Repulsive potential with very small well (De = 0.90 meV).
83	From differential elastic scattering measurements Farrar and Lee, 1972, Burgmans, Farrar, et al., 1976.
84	Average of two independent values for the well depth obtained from measurements of the total Bennewitz, Busse, et al., 1972 and differential Farrar and Lee, 1972, Burgmans, Farrar, et al., 1976 elastic scattering cross sections (0.888 and 0.905 meV, respectively). Ab initio values range from 0.78 to 1.04 meV Schaefer, McLaughlin, et al., 1970, McLaughlin and Schaefer, 1971, Liu and McLean, 1973, Bertoncini and Wahl, 1970, Kleinman and Wolfsberg, 1974, Snook and Spurling, 1975. Both experiment and theory agree that no bound vibrational level exists in the potential well, i.e. D00 =0; see Murrell, 1969, Poulat, Larsen, et al., 1975. A somewhat higher De value (De= 0.99 meV Chapman, 1975) was derived Chapman, 1975 from the temperature dependence of the relaxation time in dilute 3He. For measurements of the short-range potential (0.49 < r(Å)< 1.56) see Foreman, Rol, et al., 1974; the long-range potential is discussed by Alexander, 1970, Bruch and McGee, 1970.
85	Based on D00(He2+). From a detailed interpretation of the Hopfield continuum and the 600 Å absorption and emission bands Ginter and Brown, 1972 derives De(A 1u+) = 2.50 eV Ginter and Brown, 1972.
86	Relative to He(1S)+He(1S), i.e. I.P.(He2) = I.P.(He) - D00(He2+). The I.P. for the lowest stable state (a 3u+) is 4.25297 eV.
87	Giving the v=0,N=0 levels (real or hypothetical) of np 3g+ and np 3g- relative to 2s 3u+, v=0, N=0.

References

Go To: Top, Constants of diatomic molecules, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Ginter and Ginter, 1968
Ginter, M.L.; Ginter, D.S., Spectrum and structure of the He₂ molecule. V. Characterization of the triplet states associated with the UAO's 6-17p«pi» and 7-12p«sigma», J. Chem. Phys., 1968, 48, 2284. [all data]

Rosen, 1970
Rosen, B., International tables of selected constants. 17. Spectroscopic data relative to diatomic molecules, Pub. Pergamon Press, Oxford, 1970, 0. [all data]

Dieke, 1929
Dieke, G.H., Uber die eigenschaften einer klasse von molekultermen, insbesondere der terme des heliummolekuls, Z. Phys., 1929, 57, 71. [all data]

Dieke, Imanishi, et al., 1929
Dieke, G.H.; Imanishi, S.; Takamine, T., Neue gesetzmabigkeiten im bandenspektrum des heliums. III, Z. Phys., 1929, 57, 305. [all data]

Jevons, 1932
Jevons, W., Report on band-spectra of diatomic molecules, Pub. The Physical Society, The University Press, London, 1932, 0. [all data]

Orth and Ginter, 1976
Orth, F.B.; Ginter, M.L., The spectrum and structure of the He₂ molecule. Characterization of the triplet states associated with the UAO's 4p«sigma», 5p«sigma», and 6p«sigma», J. Mol. Spectrosc., 1976, 61, 282. [all data]

Brown and Ginter, 1973
Brown, C.M.; Ginter, M.L., Spectrum and structure of the He₂ molecule. Characterization of the singlet and triplet states associated with the UAO'S 4s, 4d«sigma», 4d«pi», and 4d«delta», J. Mol. Spectrosc., 1973, 46, 256. [all data]

Ginter, 1966
Ginter, M.L., Spectrum and structure of the He₂ molecule. IV. Characterization of the singlet and triplet states associated with the UAO's 3d«sigma», 3d«pi», and 3d«delta», J. Chem. Phys., 1966, 45, 248. [all data]

Ginter, 1965
Ginter, M.L., The spectrum and structure of the He₂ molecule. Part III. Characterization of the triplet states associated with the UAO's 3s and 2p«pi», J. Mol. Spectrosc., 1965, 18, 321. [all data]

Brown and Ginter, 1971
Brown, C.M.; Ginter, M.L., Spectrum and structure of the He₂ molecule. VI. Characterization of the states associated with the UAO's 3p«pi» and 2s, J. Mol. Spectrosc., 1971, 40, 302. [all data]

Ginter, 1965, 2
Ginter, M.L., Spectrum and structure of the He₂ molecule. I. Characterization of the states associated with the UAO's 3p«sigma» and 2s, J. Chem. Phys., 1965, 42, 561. [all data]

Hepner and Herman, 1956
Hepner, G.; Herman, L., Spectroscopie. Nouveau systeme de bandes d'emission de la molecule He₂ vers 4700 cm^-1, C.R. Acad. Sci. Paris, Ser. B, 1956, 243, 1504. [all data]

Gloersen and Dieke, 1965
Gloersen, P.; Dieke, G.H., Molecular spectra of hydrogen and helium in the infrared, J. Mol. Spectrosc., 1965, 16, 191. [all data]

Ginter, 1965, 3
Ginter, M.L., The spectrum and structure of the He₂ molecule. Part II. Characterization of the singlet states associated with the UAO's 3s and 2p«pi», J. Mol. Spectrosc., 1965, 17, 224. [all data]

Tanaka and Yoshino, 1963
Tanaka, Y.; Yoshino, K., 600-Å band of helium, J. Chem. Phys., 1963, 39, 3081. [all data]

Mies and Smith, 1966
Mies, F.H.; Smith, A.L., Bandlike structure from continuum-continuum emission: the He₂ 600-Å bands, J. Chem. Phys., 1966, 45, 994. [all data]

Smith, 1967
Smith, A.L., Observing the effect of a change in mass on de Broglie wavelength: the 600-Å bands of ³He₂, J. Chem. Phys., 1967, 47, 1561. [all data]

Chow, Smith, et al., 1971
Chow, K.W.; Smith, A.L.; Waggoner, M.G., Absorption coefficients of helium between 599 and 610 Å; transition moment for He₂ A¹ «SIGMA»_u⁺ <-- X¹ «SIGMA»_g⁺, J. Chem. Phys., 1971, 55, 4208. [all data]

Browne, 1965
Browne, J.C., Quantum mechanical potential energy curves for the ¹«PI»_u and ³«PI»_u states of He₂ and the ¹«PI»_g and ³«PI»_g states of H₂, Phys. Rev. A: Gen. Phys., 1965, 138, 9. [all data]

Gupta and Matsen, 1969
Gupta, B.K.; Matsen, F.A., Quantum-mechanical study of the F¹«PI»_u and f³«PI»_u states of He₂, J. Chem. Phys., 1969, 50, 3797. [all data]

Mulliken, 1964
Mulliken, R.S., Rare-gas and hydrogen molecule electronic states, noncrossing rule, and recombination of electrons with rare-gas and hydrogen ions, Phys. Rev., 1964, 136, 962. [all data]

Dieke and Robinson, 1950
Dieke, G.H.; Robinson, E.S., The molecular spectrum of He³, Phys. Rev., 1950, 80, 1. [all data]

Callear and Hedges, 1967
Callear, A.B.; Hedges, R.E.M., Metastability of rotationally hot dihelium at 77° K, Nature (London), 1967, 215, 1267. [all data]

Ludlum, Larson, et al., 1967
Ludlum, K.H.; Larson, L.P.; Caffrey, J.M., Jr., Activation energy for the three-body reaction of helium triplet atom with normal helium, J. Chem. Phys., 1967, 46, 127. [all data]

Ginter and Battino, 1970
Ginter, M.L.; Battino, R., Potential-energy curves for the He₂ molecule, J. Chem. Phys., 1970, 52, 4469. [all data]

Poshusta and Matsen, 1963
Poshusta, R.D.; Matsen, F.A., Potential curve of the metastable helium molecule, Phys. Rev., 1963, 132, 307. [all data]

Klein, Greenawalt, et al., 1967
Klein, D.J.; Greenawalt, E.M.; Matsen, F.A., Adjustment of ab initio potential curves, J. Chem. Phys., 1967, 47, 4820. [all data]

Gupta, 1972
Gupta, B.K., On the potential curve of the metastable helium molecule, Mol. Phys., 1972, 23, 75. [all data]

Lichten, McCusker, et al., 1974
Lichten, W.; McCusker, M.V.; Vierima, T.L., Fine structure of the metastable a³«SIGMA»_u⁺ state of the helium molecule, J. Chem. Phys., 1974, 61, 2200. [all data]

Vierima, 1975
Vierima, T.L., Determination of the sign of the spin-spin interaction in He₂(a³«SIGMA»_u⁺), J. Chem. Phys., 1975, 62, 2925. [all data]

Beck, Nicolaides, et al., 1974
Beck, D.R.; Nicolaides, C.A.; Musher, J.I., Calculation of the fine structure of the a³«SIGMA»_u⁺ state of molecular helium, Phys. Rev. A: Gen. Phys., 1974, 10, 1522. [all data]

Zhirnov and Shadrin, 1968
Zhirnov, N.I.; Shadrin, O.P., Calculation of Franck-Condon factors with Poschl-Teller wavefunctions. I. The probabilities of some vibrational transitions in the D¹«SIGMA»_u⁺-B¹«PI»_g band system of the He₂ molecule, Opt. Spectrosc. Engl. Transl., 1968, 24, 478, In original 890. [all data]

Chow and Smith, 1971
Chow, K.-W.; Smith, A.L., Repulsive potential curves from molecular continuum-continuum emission. III. He₂(X¹«SIGMA»_g⁺), J. Chem. Phys., 1971, 54, 1556. [all data]

Guberman and Goddard, 1972
Guberman, S.L.; Goddard, W.A., III, On the origin of energy barriers in the excited states of He₂, Chem. Phys. Lett., 1972, 14, 460. [all data]

Andresen and Kuppermann, 1975
Andresen, B.; Kuppermann, A., The scattering of excited by ground state atoms application to He₂, Mol. Phys., 1975, 30, 997. [all data]

Guberman and Goddard, 1975
Guberman, S.L.; Goddard, W.A., III, Nature of the excited states of He₂, Phys. Rev. A: Gen. Phys., 1975, 12, 1203. [all data]

Smith and Chow, 1970
Smith, A.L.; Chow, K.W., RKR potential and more accurate dissociation energy of He₂(A¹«SIGMA»_u⁺), J. Chem. Phys., 1970, 52, 1010. [all data]

Mukamel and Kaldor, 1971
Mukamel, S.; Kaldor, U., Potential of the A¹«SIGMA»_u⁺ state of He₂, Mol. Phys., 1971, 22, 1107. [all data]

Allison, Browne, et al., 1966
Allison, D.C.; Browne, J.C.; Dalgarno, A., Collision-induced de-activation of metastable helium, Proc. Phys. Soc. London, 1966, 89, 41. [all data]

Scott, Greenawalt, et al., 1966
Scott, D.R.; Greenawalt, E.M.; Browne, J.C.; Matsen, F.A., Quantum-mechanical potential-energy curve for the lowest ¹«SIGMA»_u⁺ state of He₂, J. Chem. Phys., 1966, 44, 2981. [all data]

Tanaka, Jursa, et al., 1958
Tanaka, Y.; Jursa, A.S.; LeBlanc, F.J., Continuous emission spectra of rare gases in the vacuum ultraviolet region. II. Neon and helium, J. Opt. Soc. Am., 1958, 48, 304. [all data]

Michaelson and Smith, 1970
Michaelson, R.C.; Smith, A.L., Time resolved studies of rare-gas molecular emission in the vacuum ultraviolet: helium and argon, Chem. Phys. Lett., 1970, 6, 1. [all data]

Mukamel and Kaldor, 1973
Mukamel, S.; Kaldor, U., Ab initio calculation of the He₂ A¹«SIGMA»_u⁺ <-- X¹«SIGMA»_g⁺ absorption spectrum, Mol. Phys., 1973, 26, 291. [all data]

Peatman and Wu, 1973
Peatman, W.B.; Wu, D.T., The 600 Å bands of helium, Chem. Phys., 1973, 2, 335. [all data]

Sando and Dalgarno, 1971
Sando, K.M.; Dalgarno, A., The absorption of radiation near 600 Å by helium, Mol. Phys., 1971, 20, 103. [all data]

Miller, Freund, et al., 1975
Miller, T.A.; Freund, R.S.; Zegarski, B.R.; Jost, R.; Lombardi, M.; Derouard, J., Observation of singlet-triplet anticrossings in ⁴He₂, J. Chem. Phys., 1975, 63, 4042. [all data]

Farrar and Lee, 1972
Farrar, J.M.; Lee, Y.T., Intermolecular potentials from crossed beam differential elastic scattering measurements. V. The attractive well of He₂, J. Chem. Phys., 1972, 56, 5801. [all data]

Burgmans, Farrar, et al., 1976
Burgmans, A.L.J.; Farrar, J.M.; Lee, Y.T., Attractive well of He-He from ³He-⁴He differential elastic scattering measurements, J. Chem. Phys., 1976, 64, 1345. [all data]

Bennewitz, Busse, et al., 1972
Bennewitz, H.G.; Busse, H.; Dohmann, H.D.; Oates, D.E.; Schrader, W., Evidence for different interaction potentials for He⁴ - He⁴ and He³ - He³ from scattering cross-section measurements, Phys. Rev. Lett., 1972, 29, 533. [all data]

Schaefer, McLaughlin, et al., 1970
Schaefer, H.F., III; McLaughlin, D.R.; Harris, F.E.; Alder, B.J., Calculation of the attractive He pair potential, Phys. Rev. Lett., 1970, 25, 988. [all data]

McLaughlin and Schaefer, 1971
McLaughlin, D.R.; Schaefer, H.F., III, Interatomic correlation energy and the van der Waals attraction between two helium atoms, Chem. Phys. Lett., 1971, 12, 244. [all data]

Liu and McLean, 1973
Liu, B.; McLean, A.D., Accurate calculation of the attractive interaction of two ground state helium atoms, J. Chem. Phys., 1973, 59, 4557. [all data]

Bertoncini and Wahl, 1970
Bertoncini, P.; Wahl, A.C., Ab initio calculation of the helium-helium ¹«SIGMA»_g⁺ potential at intermediate and large separations, Phys. Rev. Lett., 1970, 25, 991. [all data]

Kleinman and Wolfsberg, 1974
Kleinman, L.I.; Wolfsberg, M., Adiabatic correction to the van der Waals well depth of He₂, J. Chem. Phys., 1974, 61, 4366. [all data]

Snook and Spurling, 1975
Snook, I.K.; Spurling, T.H., Symmetry adapted perturbation theory of intermolecular potentials. The helium-helium interaction, J. Chem. Soc. Faraday Trans. 2, 1975, 71, 852. [all data]

Murrell, 1969
Murrell, J.N., Bound vibrational states for weakly attractive potentials, Mol. Phys., 1969, 16, 601. [all data]

Poulat, Larsen, et al., 1975
Poulat, C.; Larsen, S.Y.; Novaro, O., Is there a helium molecule?, Mol. Phys., 1975, 30, 645. [all data]

Chapman, 1975
Chapman, R., Temperature dependence of the relaxation time in dilute ³He gas: an investigation of the He-He potential, Phys. Rev. A: Gen. Phys., 1975, 12, 2333. [all data]

Foreman, Rol, et al., 1974
Foreman, P.B.; Rol, P.K.; Coffin, K.P., The repulsive ¹«SIGMA»_g⁺ He₂ potential obtained from total cross sections, J. Chem. Phys., 1974, 61, 1658. [all data]

Alexander, 1970
Alexander, M.H., Exact treatment of the long-range dipole-dipole interaction between two helium atoms, J. Chem. Phys., 1970, 52, 3354. [all data]

Bruch and McGee, 1970
Bruch, L.W.; McGee, I.J., Semiempirical helium intermolecular potential. II. Dilute gas properties, J. Chem. Phys., 1970, 52, 5884. [all data]

Ginter and Brown, 1972
Ginter, M.L.; Brown, C.M., Dissociation energies of X²«SIGMA»_u⁺ (HE₂⁺) and A¹«SIGMA»_u⁺ (He₂), J. Chem. Phys., 1972, 56, 672. [all data]

Notes

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