barium oxide, obtained by calcining witherite

Formula: BaO
Molecular weight: 153.326
IUPAC Standard InChI: InChI=1S/Ba.O
IUPAC Standard InChIKey: QVQLCTNNEUAWMS-UHFFFAOYSA-N
CAS Registry Number: 1304-28-5
Chemical structure:
This structure is also available as a 2d Mol file
Other names: barium oxide; Barium monoxide
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Gas phase ion energetics data

Go To: Top, Constants of diatomic molecules, References, Notes

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
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

View reactions leading to BaO⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	6.46 ± 0.07	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	1215.4	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	1187.6	kJ/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
6.91	EI	Koitabashi, 1994	LL
6.5 ± 0.15	EVAL	Belyaev, Gotkis, et al., 1990	LL
6.46 ± 0.07	PE	Dyke, Feher, et al., 1987	LBLHLM
6.8 ± 0.2	EI	Murad, 1981	LLK
6.9 ± 0.1	EI	Rauh and Ackermann, 1976	LLK
6.5 ± 0.2	EI	Hilpert, Naoumidis, et al., 1975	LLK
7. ± 1.	EI	Farber and Srivastava, 1975	LLK
6.97 ± 0.12	EI	Panchenkov, Gusarov, et al., 1973	LLK
6.8 ± 0.5	EI	Pupp, Yamdagni, et al., 1969	RDSH
6.5 ± 0.3	EI	Mesnard, Uzan, et al., 1963	RDSH
6.89 ± 0.03	PE	Dyke, Feher, et al., 1987	Vertical value; LBLHLM

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
Ba⁺	~11.	O	EI	Koitabashi, 1994	LL
Ba⁺	10.95 ± 0.18	O	EI	Panchenkov, Gusarov, et al., 1973	LLK
Ba⁺	13.7 ± 0.5	O	EI	Mesnard, Uzan, et al., 1966	RDSH
Ba⁺	13.2 ± 0.2	O	EI	Mesnard, Uzan, et al., 1963	RDSH

Constants of diatomic molecules

Go To: Top, Gas phase ion energetics data, References, Notes

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

Data collected through September, 1976

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 ¹³⁸Ba¹⁶O
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
[36490-38620] 1
↳Field, Capelle, et al., 1975
B (¹Π)	32866.₄	488 H	3.6								B ↔ X R	32775 H
B (¹Π)	↳missing citation
A' ¹Π	17691 2	443 H	1.66		0.2252 3	0.0013₀		(0.00000023)		2.285	A' ↔ X 4 R	17578 H
A' ¹Π	↳Hsu, Krugh, et al., 1974; Pruett and Zare, 1975; missing citation; Engelke, Sander, et al., 1976
a ³Π₀⁺	17586.₅ 2	449.₀ 5	2.5		0.2254₄ 5	0.0013₈
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 ³Π₁	17442 2	[445] 5	(4.5)		[0.2254] 5					2.289
a ³Π₂	17393 2	5			5
A ¹Σ⁺	16807.₂	499.₇ 6 Z	1.6₄		0.25832 6	0.001070		0.00000028		2.1338	A ↔ X R 7 8	16722.25 Z
	↳missing citation; missing citation; missing citation; Sakurai, Johnson, et al., 1970; Dagdigian, Cruse, et al., 1974
	Microwave optical double resonance
	↳Field, Bradford, et al., 1972; Field, Bradford, et al., 1972, 2; Field, English, et al., 1973
X ¹Σ⁺	0	669.76 9 Z	2.02₈ 10	-0.003₅	0.3126140 9	0.0013921	-0.00000433	2.724E-07		1.939692 11 12
	↳Wharton and Klemperer, 1963; Hoeft, Lovas, et al., 1970; Tiemann, Bojaschewsky, et al., 1974
	Mol. beam electric 13 and magn. reson. 14
	↳Wharton, Kaufman, et al., 1962; Brooks and Kaufman, 1965

Notes

Nineteen ¹Σ⁺ vibronic levels belonging to two or more perturbed electronic states. 17

³Π₂, ³Π₁, ³Π₀, and ¹Π, [see Field, 1974] correspond to Q, Z, Y, and X, respectively, of Lagerqvist, Lind, et al., 1949, Kovacs and Lagerqvist, 1950.

Only v=12,17,18 have been rotationally analyzed Pruett and Zare, 1975. In addition, constants for v=2,3,4 have been derived Lagerqvist, Lind, et al., 1949, Kovacs and Lagerqvist, 1950 from perturbations Field, 1974 in v=3,4,5, respectively, of A ¹Σ⁺. Σ⁺

Radiative lifetime τ(v=13...17)= 9 μs Pruett and Zare, 1975. Similar lifetimes observed by Sakurai, Johnson, et al., 1970,2O can be attributed to either A' ¹Π or a ³Π_i; see Field, Jones, et al., 1974.

From perturbations in A ¹Σ+ Lagerqvist, Lind, et al., 1949, Kovacs and Lagerqvist, 1950, Field, 1974. Field, 1974 has adopted the following constants a ³Π_i; T_e = 17483 Field, 1974, a ³Π_i; A= -105 Field, 1974, a ³Π_i; ω_e= 448.3 Field, 1974, a ³Π_i; ω_ex_e=2.39 Field, 1974, a ³Π_i; B_e=0.2244 Field, 1974, a ³Π_i α_e=0.0014 Field, 1974.

Partially deperturbed constants. Numerous interactions with levels of a ³Π_i and A' ¹Π, except in v=0 which is unperturbed Lagerqvist, Lind, et al., 1949, Kovacs and Lagerqvist, 1950, Field, 1974. Potential curve Singh and Rai, 1966, Tawde and Tulasigeri, 1975.

Radiative lifetime τ(v=0) = 0.356 μs; f₀₀(A←X) = 0.00026 Johnson, 1972. Slight variation of τ with v.

Relative intensities Vaidya, Desai, et al., 1964, Walvekar and Korwar, 1969, Degen, Brown, et al., 1971, Best and Hoffman, 1973; Franck-Condon factors Ortenberg, Glasko, et al., 1964, Wentink and Spindler, 1972, Tawde and Tulasigeri, 1975.

The ground state constants have been derived Field, Capelle, et al., 1975 from a combination of microwave rotational constants Hoeft, Lovas, et al., 1970, Tiemann, Bojaschewsky, et al., 1974, electronic band origins Lagerqvist, Lind, et al., 1949, and data on higher vibrational levels (v ≤ 34) obtained by optical-optical double resonance photoluminescence spectroscopy. They were used for the construction of the RKR potential curve up to v=40 Field, Capelle, et al., 1975.

ω_ez_e = -6.₃E-5.

From the Dunham corrected microwave B_e value in Tiemann, Bojaschewsky, et al., 1974.

Microwave sp. 18

μel (v)=[7.934 + 0.042(v+1/2)] D.

g_J = (-)0.103.

By extrapolation of the highest observed ground state levels (v=0,J) populated in the reaction Ba+CO₂ under single-collision conditions Dagdigian, Cruse, et al., 1974. Compatible with lower bounds obtained from the short-wavelength limits of the Ba+NO₂ Ottinger and Zare, 1970, Jonah, Zare, et al., 1972 and Ba+ClO₂ Engelke, Sander, et al., 1976 chemiluminescence spectra. Flame photometric values 16,27,36, if corrected to a ¹Σ ground state, are near 5.6₉ eV. Earlier measurements reviewed in Schofield, 1967, Gaydon, 1968.

Electron impact appearance potential Panchenkov, Gusarov, et al., 1973, Rauh and Ackermann, 1976.

Optical-optical double resonance laser spectroscopy.

Values of eqQ(^135,137Ba) in Hoeft, Lovas, et al., 1970, Tiemann, Bojaschewsky, et al., 1974.

References

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

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Koitabashi, 1994
Koitabashi, M., Mass spectrum of barium oxide vapor, Jpn. J. Appl. Phys., 1994, 33, 5995. [all data]

Belyaev, Gotkis, et al., 1990
Belyaev, V.N.; Gotkis, I.S.; Lebedeva, N.L.; Krasnov, K.S., Ionization potentials of MX molecules (M = Ca, Sr, Ba; X = F, Cl, Br, I, OH, O), Russ. J. Phys. Chem., 1990, 64, 773. [all data]

Dyke, Feher, et al., 1987
Dyke, J.M.; Feher, M.; Gravenor, B.W.J.; Morris, A., High-temperature photoelectron spectroscopy: A study of the alkaline earth oxides SrO and BaO, J. Phys. Chem., 1987, 91, 4476. [all data]

Murad, 1981
Murad, E., Thermochemical properties of the gaseous alkaline earth monohydroxides, J. Chem. Phys., 1981, 75, 4080. [all data]

Rauh and Ackermann, 1976
Rauh, E.G.; Ackermann, R.J., Erratum: First ionization potentials of some refractory oxide vapors, J. Chem. Phys., 1976, 64, 1862. [all data]

Hilpert, Naoumidis, et al., 1975
Hilpert, K.; Naoumidis, A.; Wolff, G., Mass spectrometric study of the evaporation of BaAl₂O₄, High Temp. Sci., 1975, 7, 1. [all data]

Farber and Srivastava, 1975
Farber, M.; Srivastava, R.D., The dissociation energy of barium oxide, High Temp. Sci., 1975, 7, 74. [all data]

Panchenkov, Gusarov, et al., 1973
Panchenkov, I.G.; Gusarov, A.V.; Gorokhov, L.N., Dissociation energy of the barium oxide molecule, Russ. J. Phys. Chem., 1973, 47, 55. [all data]

Pupp, Yamdagni, et al., 1969
Pupp, C.; Yamdagni, R.; Porter, R.F., Mass spectrometric study of the evaporation of BaMoO₄ and BaWO₄, J. Inorg. Nucl. Chem., 1969, 31, 2021. [all data]

Mesnard, Uzan, et al., 1963
Mesnard, G.; Uzan, R.; Cabaud, B., Potentiels d'apparition des ions obtenus dans un spectrometre de masse a partir d'oxydes alcalino-terreux, Cahiers Phys., 1963, 17, 333. [all data]

Mesnard, Uzan, et al., 1966
Mesnard, G.; Uzan, R.; Cabaud, B., Etude au spectrometre de masse des produits d'evaporation du bioxyde de titane et du titanate de baryum, Rev. Phys. Appl., 1966, 1, 123. [all data]

Field, Capelle, et al., 1975
Field, R.W.; Capelle, G.A.; Revelli, M.A., Optical-optical double resonance laser spectroscopy of BaO, J. Chem. Phys., 1975, 63, 3228. [all data]

Hsu, Krugh, et al., 1974
Hsu, C.J.; Krugh, W.D.; Palmer, H.B.; Obenauf, R.H.; Aten, C.F., A new electronic band system of BaO, J. Mol. Spectrosc., 1974, 53, 273. [all data]

Pruett and Zare, 1975
Pruett, J.G.; Zare, R.N., Lifetime-separated spectroscopy: observation and rotational analysis of the BaO A'¹Π state, J. Chem. Phys., 1975, 62, 2050. [all data]

Engelke, Sander, et al., 1976
Engelke, F.; Sander, R.K.; Zare, R.N., Crossed-beam chemiluminescent studies of alkaline earth atoms with ClO₂, J. Chem. Phys., 1976, 65, 1146. [all data]

Sakurai, Johnson, et al., 1970
Sakurai, K.; Johnson, S.E.; Broida, H.P., Laser-induced fluoroscence of BaO, J. Chem. Phys., 1970, 52, 1625. [all data]

Dagdigian, Cruse, et al., 1974
Dagdigian, P.J.; Cruse, H.W.; Schultz, A.; Zare, R.N., Product state analysis of BaO from the reactions Ba + CO₂ and Ba + O₂, J. Chem. Phys., 1974, 61, 4450. [all data]

Field, Bradford, et al., 1972
Field, R.W.; Bradford, R.S.; Harris, D.O.; Broida, H.P., Microwave optical double resonance spectroscopy of BaO, J. Chem. Phys., 1972, 56, 4712. [all data]

Field, Bradford, et al., 1972, 2
Field, R.W.; Bradford, R.S.; Broida, H.P.; Harris, D.O., Excited state microwave spectroscopy of the A¹Σ state of BaO, J. Chem. Phys., 1972, 57, 2209. [all data]

Field, English, et al., 1973
Field, R.W.; English, A.D.; Tanaka, T.; Harris, D.O.; Jennings, D.A., Microwave optical double resonance spectroscopy with a cw dye laser: BaO X¹Σ and A¹Σ, J. Chem. Phys., 1973, 59, 2191. [all data]

Wharton and Klemperer, 1963
Wharton, L.; Klemperer, W., Microwave spectrum of BaO, J. Chem. Phys., 1963, 38, 2705. [all data]

Hoeft, Lovas, et al., 1970
Hoeft, J.; Lovas, F.J.; Tiemann, E.; Torring, T., Microwave spectrum of BaO, Z. Naturforsch. A, 1970, 25, 1750. [all data]

Tiemann, Bojaschewsky, et al., 1974
Tiemann, E.; Bojaschewsky, M.; Sauter-Servaes, C.; Torring, T., Rotationsspektrum von BaO, Z. Naturforsch. A, 1974, 29, 1692. [all data]

Wharton, Kaufman, et al., 1962
Wharton, L.; Kaufman, M.; Klemperer, W., Electric resonance spectrum and dipole moment of BaO, J. Chem. Phys., 1962, 37, 621. [all data]

Brooks and Kaufman, 1965
Brooks, R.; Kaufman, M., Rotational magnetic moment of BaO, J. Chem. Phys., 1965, 43, 3406. [all data]

Field, 1974
Field, R.W., Assignment of the lowest ³Π and ¹Π states of CaO, SrO, and BaO, J. Chem. Phys., 1974, 60, 2400. [all data]

Lagerqvist, Lind, et al., 1949
Lagerqvist, A.; Lind, E.; Barrow, R.F., Band-spectrum of barium oxide, Nature (London), 1949, 164, 923. [all data]

Kovacs and Lagerqvist, 1950
Kovacs, I.; Lagerqvist, A., Perturbations in the BaO spectrum, J. Chem. Phys., 1950, 18, 1683. [all data]

Field, Jones, et al., 1974
Field, R.W.; Jones, C.R.; Broida, H.P., Gas-phase reaction of Ba with N₂O. II. Mechanism of reaction, J. Chem. Phys., 1974, 60, 4377. [all data]

Singh and Rai, 1966
Singh, R.B.; Rai, D.K., Potential curves for some diatomic molecules: P₂, PN, SiN, NBr, BaO, BeF, SiF & SnF, Indian J. Pure Appl. Phys., 1966, 4, 102. [all data]

Tawde and Tulasigeri, 1975
Tawde, N.R.; Tulasigeri, V.G., Franck-Condon factors, r-centroids and electronic transition moment variation with internuclear distance of the A¹Σ-X¹Σ band system of BaO using RKR potentials, Acta Phys. Acad. Sci. Hung., 1975, 38, 299. [all data]

Johnson, 1972
Johnson, S.E., Measured radiative lifetimes and electronic quenching cross sections of BaO(A¹Σ), J. Chem. Phys., 1972, 56, 149. [all data]

Vaidya, Desai, et al., 1964
Vaidya, W.M.; Desai, D.D.; Bidaye, R.G., Intensity distribution in the A¹Σ-X¹Σ system of BaO, J. Quant. Spectrosc. Radiat. Transfer, 1964, 4, 353. [all data]

Walvekar and Korwar, 1969
Walvekar, A.P.; Korwar, V.M., Vibrational transition probabilities of the bands of the BaO (A¹Σ-X¹Σ) system, J. Phys. B:, 1969, 2, 115. [all data]

Degen, Brown, et al., 1971
Degen, V.; Brown, N.; Romick, G.J., Rotational and vibrational temperatures of BaO from a barium release at 170 km, and the synthetic spectrum of BaO in the region 4700 Å to 15,500 Å, Planet. Space Sci., 1971, 19, 1625. [all data]

Best and Hoffman, 1973
Best, G.T.; Hoffman, H.S., The electronic transition moment of the A¹Σ-X¹Σ band system of BaO, J. Quant. Spectrosc. Radiat. Transfer, 1973, 13, 69. [all data]

Ortenberg, Glasko, et al., 1964
Ortenberg, F.S.; Glasko, V.B.; Dmitriev, A.I., Vibrational transition probabilities for band systems of some diatomic oxides. II., Sov. Astron. Engl. Transl., 1964, 8, 258, In original 332. [all data]

Wentink and Spindler, 1972
Wentink, T., Jr.; Spindler, R.J., Jr., Franck-Condon factors, r-centroids and oscillator strength of BaO (A¹Σ-X¹Σ), J. Quant. Spectrosc. Radiat. Transfer, 1972, 12, 129. [all data]

Ottinger and Zare, 1970
Ottinger, Ch.; Zare, R.N., Crossed beam chemiluminescence, Chem. Phys. Lett., 1970, 5, 243. [all data]

Jonah, Zare, et al., 1972
Jonah, C.D.; Zare, R.N.; Ottinger, Ch., Crossed-beam chemiluminescence studies of some group IIa metal oxides, J. Chem. Phys., 1972, 56, 263. [all data]

Schofield, 1967
Schofield, K., The bond dissociation energies of group IIA diatomic oxides, Chem. Rev., 1967, 67, 707. [all data]

Gaydon, 1968
Gaydon, A.G., Dissociation energies and spectra of diatomic molecules, Chapman and Hall, Ltd., 3rd Edition, London, 1968, 1. [all data]

Notes

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

Symbols used in this document:

AE Appearance energy

IE (evaluated) Recommended ionization energy
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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AE	Appearance energy
IE (evaluated)	Recommended ionization energy