Dipotassium

Formula: K₂
Molecular weight: 78.1966
IUPAC Standard InChI: InChI=1S/2K
IUPAC Standard InChIKey: ZDHURYWHEBEGHO-UHFFFAOYSA-N
CAS Registry Number: 25681-80-5
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript.
Permanent link for this species. Use this link for bookmarking this species for future reference.
Information on this page:
Data at other public NIST sites:
- Gas Phase Kinetics Database
Options:
- Switch to SI units

Gas phase thermochemistry data

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Constants of diatomic molecules, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	29.560	kcal/mol	Review	Chase, 1998	Data last reviewed in December, 1983
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	59.682	cal/mol*K	Review	Chase, 1998	Data last reviewed in December, 1983

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
C_p = heat capacity (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

View table.

Temperature (K)	298. to 1300.	1300. to 6000.
A	5.415581	7.412359
B	12.80000	-1.382941
C	-13.46240	0.276767
D	3.826100	-0.018846
E	0.083536	2.970591
F	27.77010	32.06570
G	63.45301	73.42949
H	29.56099	29.56099
Reference	Chase, 1998	Chase, 1998
Comment	Data last reviewed in December, 1983	Data last reviewed in December, 1983

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Constants of diatomic molecules, References, Notes

Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

K₈⁺ + Dipotassium = (K₈⁺ • )

By formula: K₈⁺ + K₂ = (K₈⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20.3	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₉⁺ + Dipotassium = (K₉⁺ • )

By formula: K₉⁺ + K₂ = (K₉⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.7	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₁⁺ + Dipotassium = (K₁₁⁺ • )

By formula: K₁₁⁺ + K₂ = (K₁₁⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.7	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₃⁺ + Dipotassium = (K₁₃⁺ • )

By formula: K₁₃⁺ + K₂ = (K₁₃⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.4	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₃⁺ + Dipotassium = (K₃⁺ • )

By formula: K₃⁺ + K₂ = (K₃⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.9	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₄⁺ + Dipotassium = (K₄⁺ • )

By formula: K₄⁺ + K₂ = (K₄⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.8	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₆⁺ + Dipotassium = (K₆⁺ • )

By formula: K₆⁺ + K₂ = (K₆⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.1	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₅⁺ + Dipotassium = (K₅⁺ • )

By formula: K₅⁺ + K₂ = (K₅⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	18.2	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₇⁺ + Dipotassium = (K₇⁺ • )

By formula: K₇⁺ + K₂ = (K₇⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	21.7	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₀⁺ + Dipotassium = (K₁₀⁺ • )

By formula: K₁₀⁺ + K₂ = (K₁₀⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.1	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₂⁺ + Dipotassium = (K₁₂⁺ • )

By formula: K₁₂⁺ + K₂ = (K₁₂⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.4	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Ion clustering data, Constants of diatomic molecules, References, Notes

Data evaluated as indicated in comments:
L - Sharon G. Lias

Data compiled as indicated in comments:
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	4.062 ± 0.0015	eV	N/A	N/A	L

Electron affinity determinations

EA (eV)	Method	Reference	Comment
0.497 ± 0.012	LPES	Eaton, Sarkas, et al., 1992	Vertical Detachment Energy: 0.550±0.010 eV.; B
0.493 ± 0.012	LPES	McHugh, Eaton, et al., 1989	Vertical Detachment Energy: 0.550±0.010 eV; B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
4.0637 ± 0.0002	PI	Kappes, Radi, et al., 1985	LBLHLM
4.0637 ± 0.0003	PI	Broyer, Chevaleyre, et al., 1985	LBLHLM
4.06075 ± 0.00015	LS	Leutwyler, Hofmann, et al., 1981	LLK
4.059 ± 0.001	LS	Herrmann, Schumacher, et al., 1978	LLK
4.0607 ± 0.0001	PI	Herrmann, Schumacher, et al., 1978	LLK
4.05 ± 0.05	PI	Herrmann, Schumacher, et al., 1978	LLK
4.059 ± 0.001	PI	Herrmann, Leutwyler, et al., 1978	LLK
3.9	EI	Zmbov, Wu, et al., 1977	LLK
4.0 ± 0.1	PI	Foster, Leckenby, et al., 1969	RDSH
~4.1	S	Robertson and Barrow, 1961	RDSH

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
K⁺	4.85	K	PI	Herrmann, Leutwyler, et al., 1978	LLK

Ion clustering data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Constants of diatomic molecules, References, Notes

Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

K₃⁺ + Dipotassium = (K₃⁺ • )

By formula: K₃⁺ + K₂ = (K₃⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.9	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₄⁺ + Dipotassium = (K₄⁺ • )

By formula: K₄⁺ + K₂ = (K₄⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.8	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₅⁺ + Dipotassium = (K₅⁺ • )

By formula: K₅⁺ + K₂ = (K₅⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	18.2	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₆⁺ + Dipotassium = (K₆⁺ • )

By formula: K₆⁺ + K₂ = (K₆⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.1	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₇⁺ + Dipotassium = (K₇⁺ • )

By formula: K₇⁺ + K₂ = (K₇⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	21.7	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₈⁺ + Dipotassium = (K₈⁺ • )

By formula: K₈⁺ + K₂ = (K₈⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20.3	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₉⁺ + Dipotassium = (K₉⁺ • )

By formula: K₉⁺ + K₂ = (K₉⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.7	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₀⁺ + Dipotassium = (K₁₀⁺ • )

By formula: K₁₀⁺ + K₂ = (K₁₀⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.1	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₁⁺ + Dipotassium = (K₁₁⁺ • )

By formula: K₁₁⁺ + K₂ = (K₁₁⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.7	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₂⁺ + Dipotassium = (K₁₂⁺ • )

By formula: K₁₂⁺ + K₂ = (K₁₂⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.4	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

K₁₃⁺ + Dipotassium = (K₁₃⁺ • )

By formula: K₁₃⁺ + K₂ = (K₁₃⁺ • K₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.4	kcal/mol	PDiss	Brechignac, Cahuzac, et al., 1990	gas phase

Constants of diatomic molecules

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, References, Notes

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

Data collected through January, 1977

Symbols used in the table of constants
Symbol	Meaning
State	electronic state and / or symmetry symbol
T_e	minimum electronic energy (cm^-1)
ω_e	vibrational constant – first term (cm^-1)
ω_ex_e	vibrational constant – second term (cm^-1)
ω_ey_e	vibrational constant – third term (cm^-1)
B_e	rotational constant in equilibrium position (cm^-1)
α_e	rotational constant – first term (cm^-1)
γ_e	rotation-vibration interaction constant (cm^-1)
D_e	centrifugal distortion constant (cm^-1)
β_e	rotational constant – first term, centrifugal force (cm^-1)
r_e	internuclear distance (Å)
Trans.	observed transition(s) corresponding to electronic state
ν₀₀	position of 0-0 band (units noted in table)

Diatomic constants for ³⁹K₂
State	T_e	ω_e	ω_ex_e	ω_ey_e	B_e	α_e	γ_e	D_e	β_e	r_e	Trans.	ν₀₀
Unidentified diffuse emission bands, 17460 - 17840 cm^-1.
↳Rebbeck and Vaughan, 1971
Diffuse bands close to lines of the principal series of K; fragments of additional systems.
↳Kuhn, 1932; Chakraborti, 1937; Okuda, 1936
G	28091	64.9₀ 1 H	0.55								G ← X R	28077 H
G	↳Yoshinaga, 1937
F	27571	62.2₉ 1 H	0.2₄								F ← X R	27556 H
F	↳Yoshinaga, 1937
State	T_e	ω_e	ω_ex_e	ω_ey_e	B_e	α_e	γ_e	D_e	β_e	r_e	Trans.	ν₀₀
E	26494.₀	61.₈ 2 H	0.2₈								E ← X R	26478.₉ H
E	↳Yoshinaga, 1937; Sinha, 1950
D	24627.7	61.60 H	0.90 3	0.0010							D ← X R	24612.3 H
D	↳Sinha, 1948
C ¹Π_u	22969.4₃	61.48₅ Z	0.13₃		0.04404	0.00011	3E-6			4.433	C ← X R	22954.2₀ Z
C ¹Π_u	↳Yamamoto, 1929; Sinha, 1948; Robertson and Barrow, 1961
B ¹Π_u	15376.7₄	75.00	0.3876 4	4.366E-3	0.04876₃ 5	0.00024		8.25E-₈		4.212₅	B 6 ↔ X 7 R	15368.2₀ Z
B ¹Π_u	↳Loomis, 1931; Loomis and Nusbaum, 1932; Tango, Link, et al., 1968
State	T_e	ω_e	ω_ex_e	ω_ey_e	B_e	α_e	γ_e	D_e	β_e	r_e	Trans.	ν₀₀
A ¹Σ_u⁺	11681.9	69.09 H	0.153		8						A ↔ X R	11670.5 H
A ¹Σ_u⁺	↳Crane and Christy, 1930; Sorokin and Lankard, 1971
a ³Σ_u⁺	Not observed; scattering calculations predict a very shallow potential minimum at ~8.7 Å.
a ³Σ_u⁺	↳Geittner, 1975
X ¹Σ_g⁺	0	92.021 Z	0.2829 9	-2.055E-3	0.056743	0.000165 10		8.63E-8		3.9051 11
X ¹Σ_g⁺	↳Kusch, Millman, et al., 1939; Logan, Cote, et al., 1952; Brooks, Anderson, et al., 1963

Notes

Analysis by Yoshinaga, 1937; not confirmed by Sinha, 1950.

Average of the constants obtained by Yoshinaga, 1937, Sinha, 1950.

ω_ez_e = -0.00030; convergence at 25590.

ω_ez_e = -0.0001830; vibrational constants for v'≤ 25 from low-resolution magnetic rotation spectra. Higher vibrational levels converge rapidly at 17160 cm^-1 above X ¹Σ_g⁺, v=0. T_e is from the analysis of high-resolution laser-induced fluorescence spectra Tango, Link, et al., 1968.

Recalculated by Tango, Link, et al., 1968, from the data of Loomis, 1931.

Radiative lifetime τ(v = 6,7,8) = 12.4 ns Tango and Zare, 1970; Baumgartner, Demtroder, et al., 1970 measured 9.7 ns.

Absorption cross sections Lapp and Harris, 1966.

A complex magnetic rotation spectrum has been observed which may be due to perturbations of A ¹Σ_u⁺ by an unidentified ³Π state Carroll, 1937.

Vibrational and rotational constants from the laser-induced B ≥ X fluorescence spectrum Tango, Link, et al., 1968.

α_v= -7.2E-6(v+1/2)² + 1.5E-7(v+1/2)³. See 9.

Mol. beam magn. reson. 14

From the convergence limit of B ¹Π_u. Thermochemical value [ Lewis, 1931, recalculated Loomis and Nusbaum, 1932] 0.56 eV.

Photoionization of K₂ Foster, Leckenby, et al., 1969; in agreement with limits (3.57 ≤ I.P. ≤ 4.11 eV) obtained from chemi-ionization thresholds Lee and Mahan, 1965, Williams, 1967, Robertson and Barrow, 1961 estimate 4.09 eV.

g_J = 0.02163 μ_N Brooks, Anderson, et al., 1963. For NMR spectrum and potassium eqQ see Kusch, Millman, et al., 1939, Logan, Cote, et al., 1952.

From D₀⁰(K₂) + I.P.(K) - I.P.(K₂). The experimentally observed limits (photoionization of potassium vapor, are 0.74 eV ≤ D₀⁰ ≤ 1.27 eV Williams, 1967. Theoretical calculations Bellomonte, Cavaliere, et al., 1974 give l eV.

Theoretical calculations Bellomonte, Cavaliere, et al., 1974.

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Constants of diatomic molecules, Notes

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Brechignac, Cahuzac, et al., 1990
Brechignac, C.; Cahuzac, P.; Carlier, F.; De Frutos, M.; Leyniger, J., Cohesive Energies of (K)n+ 5<n<200 from Photoevaporation Experiments, J. Chem. Phys., 1990, 93, 10, 7449, https://doi.org/10.1063/1.459418 . [all data]

Eaton, Sarkas, et al., 1992
Eaton, J.G.; Sarkas, H.W.; Arnold, S.T.; Mchugh, K.M.; Bowen, K.H., Negative Ion Photoelectron Spectroscopy of the Heteronuclear Alkali-Metal Dimer and Trimer Anions - NaK-, KRb-, RbCS-, KCs-, Na2K-, and K2Cs, Chem. Phys. Lett., 1992, 193, 1-3, 141, https://doi.org/10.1016/0009-2614(92)85697-9 . [all data]

McHugh, Eaton, et al., 1989
McHugh, K.M.; Eaton, J.G.; Lee, G.H.; Sarkas, H.W.; Kidder, L.H.; Snodgrass, J.T.; Manaa, M.R.; Bowen, K.H., Photoelectron Spectra of the alkali metal cluster Anions: Na-,n=2-5, K-,n=2-7, Rb-,n=2-3, and Cs-,n=2-3, J. Chem. Phys., 1989, 91, 6, 3792, https://doi.org/10.1063/1.456861 . [all data]

Kappes, Radi, et al., 1985
Kappes, M.M.; Radi, P.; Schar, M.; Schumacher, E., Photoionization measurements on dialkali monohalides generated in supersonic nozzle beams, Chem. Phys. Lett., 1985, 113, 243. [all data]

Broyer, Chevaleyre, et al., 1985
Broyer, M.; Chevaleyre, J.; Delacretaz, G.; Fayet, P.; Woste, L., One- and two-photon ionization of alkaline clusters, Surf. Sci., 1985, 156, 342. [all data]

Leutwyler, Hofmann, et al., 1981
Leutwyler, S.; Hofmann, M.; Harri, H.-P.; Schumacher, E., The adiabatic ionization potentials of the alkali dimers Na₂, NaK and K₂, Chem. Phys. Lett., 1981, 77, 257. [all data]

Herrmann, Schumacher, et al., 1978
Herrmann, A.; Schumacher, E.; Woste, L., Preparation and photoionization potentials of molecules of sodium, potassium and mixed atoms, J. Chem. Phys., 1978, 68, 2327. [all data]

Herrmann, Leutwyler, et al., 1978
Herrmann, A.; Leutwyler, S.; Schumacher, E.; Woste, L., 38. On metal-atom clusters IV. Photoionization thresholds and multiphoton ionization spectra of alkali-metal molecules, Helv. Chim. Acta, 1978, 61, 453. [all data]

Zmbov, Wu, et al., 1977
Zmbov, K.F.; Wu, C.H.; Ihle, H.R., A mass spectrometric study of heteronuclear diatomic alkali metal molecules. Dissociation energies ionization potentials of NaLi, KLi, NaK, J. Chem. Phys., 1977, 67, 4603. [all data]

Foster, Leckenby, et al., 1969
Foster, P.J.; Leckenby, R.E.; Robbins, E.J., The ionization potentials of clustered alkali metal atoms, J. Phys. B:, 1969, 2, 478. [all data]

Robertson and Barrow, 1961
Robertson, E.W.; Barrow, R.F., Rotational analysis oi the C¹π_u-X1⁺_g system of K₂, and the ionisation potential of K₂, Proc. Chem. Soc., 1961, 329. [all data]

Rebbeck and Vaughan, 1971
Rebbeck, M.M.; Vaughan, J.M., Unidentified diffuse bands in the spectrum of potassium, J. Phys. B:, 1971, 4, 258. [all data]

Kuhn, 1932
Kuhn, H., Uber spektren von unecht gebundenen molekulen (polarisationsmolekulen) K₂, Na₂, Cs₂ und verbreiterung von absorptionslinien, Z. Phys., 1932, 76, 782. [all data]

Chakraborti, 1937
Chakraborti, B.K., On a new type of absorption bands of potassium vapour, Indian J. Phys., 1937, 10, 155. [all data]

Okuda, 1936
Okuda, T., Narrow continuous band of potassium in the extreme red, Nature (London), 1936, 138, 168. [all data]

Yoshinaga, 1937
Yoshinaga, H., New ultraviolet absorption bands of sodium and potassium molecules, Proc. Phys. Math. Soc. Jpn., 1937, 19, 847. [all data]

Sinha, 1950
Sinha, S.P., Ultra-violet bands of K₂, Proc. Phys. Soc. London Sect. A, 1950, 63, 952. [all data]

Sinha, 1948
Sinha, S.P., Blue and ultra-violet bands of K₂, Proc. Phys. Soc. London, 1948, 60, 436. [all data]

Yamamoto, 1929
Yamamoto, Revised by Crane and Christy, 1930, 1929, 355. [all data]

Loomis, 1931
Loomis, F.W., Rotational structure of the red bands of potassium, Phys. Rev., 1931, 38, 2153. [all data]

Loomis and Nusbaum, 1932
Loomis, F.W.; Nusbaum, R.E., Magnetic rotation spectrum and heat of dissociation of the potassium molecule, Phys. Rev., 1932, 39, 89. [all data]

Tango, Link, et al., 1968
Tango, W.J.; Link, J.K.; Zare, R.N., Spectroscopy of K₂ using laser-induced fluorescence, J. Chem. Phys., 1968, 49, 4264. [all data]

Crane and Christy, 1930
Crane, W.O.; Christy, A., Vibrational quantum analysis of the potassium infrared absorption bands, Phys. Rev., 1930, 36, 421. [all data]

Sorokin and Lankard, 1971
Sorokin, P.P.; Lankard, J.R., Emission spectra of alkali-metal molecules observed with a heat-pipe discharge tube, J. Chem. Phys., 1971, 55, 3810. [all data]

Geittner, 1975
Geittner, P., Bestimmung der Triplett-Potentialdaten fur das K₂-Stossmolekul, Z. Phys., 1975, 272, 359. [all data]

Kusch, Millman, et al., 1939
Kusch, P.; Millman, S.; Rabi, I.I., The nuclear magnetic moments of N¹⁴, Na²³, K³⁹ and Cs¹³³, Phys. Rev., 1939, 55, 1176. [all data]

Logan, Cote, et al., 1952
Logan, R.A.; Cote, R.E.; Kusch, P., The sign of the quadrupole interaction energy in diatomic molecules, Phys. Rev., 1952, 86, 280. [all data]

Brooks, Anderson, et al., 1963
Brooks, R.A.; Anderson, C.H.; Ramsey, N.F., Rotational magnetic moments of diatomic alkalis, Phys. Rev. Lett., 1963, 10, 441. [all data]

Tango and Zare, 1970
Tango, W.J.; Zare, R.N., Radiative lifetime of the B¹Π_u state of K₂, J. Chem. Phys., 1970, 53, 3094. [all data]

Baumgartner, Demtroder, et al., 1970
Baumgartner, G.; Demtroder, W.; Stock, M., Lifetime-measurements of alkali-molecules excited by different laserlines, Z. Phys., 1970, 232, 462. [all data]

Lapp and Harris, 1966
Lapp, M.; Harris, L.P., Absorption cross sections of alkali-vapor molecules: I. Cs₂ in the visible. II. K₂ in the red, J. Quant. Spectrosc. Radiat. Transfer, 1966, 6, 169. [all data]

Carroll, 1937
Carroll, T., Magnetic rotation spectra of diatomic molecules, Phys. Rev., 1937, 52, 822. [all data]

Lewis, 1931
Lewis, L.C., Die bestimmung des gleichgewichts zwischen den atomen und den molekulen eines alkalidampfes mit einer molekularstrahlmethode, Z. Phys., 1931, 69, 786. [all data]

Lee and Mahan, 1965
Lee, Y.-T.; Mahan, B.H., Photosensitized ionization of alkali-metal vapors, J. Chem. Phys., 1965, 42, 2893. [all data]

Williams, 1967
Williams, R.A., Photoionization of potassium vapor, J. Chem. Phys., 1967, 47, 4281. [all data]

Bellomonte, Cavaliere, et al., 1974
Bellomonte, L.; Cavaliere, P.; Ferrante, G., Alkali molecular ion energies and expectation values in a model-potential treatment, J. Chem. Phys., 1974, 61, 3225. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Constants of diatomic molecules, References

Symbols used in this document:

AE	Appearance energy
EA	Electron affinity
IE (evaluated)	Recommended ionization energy
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
Customer support for NIST Standard Reference Data products.