Calcium

Formula: Ca₂
Molecular weight: 80.156
IUPAC Standard InChI: InChI=1S/2Ca
IUPAC Standard InChIKey: CPGKMLVTFNUAHL-UHFFFAOYSA-N
CAS Registry Number: 12595-85-6
Chemical structure:
This structure is also available as a 2d Mol file
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Constants of diatomic molecules

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

Data collected through July, 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 ⁴⁰Ca₂
State	T_e	ω_e	ω_ex_e	ω_ey_e	B_e	α_e	γ_e	D_e	r_e	Trans.	ν₀₀
A band system in the region 16100 - 16900 cm^-1 and assigned to Ca₂ by Kovalenok and Sokolov, 1967 is in all probability the same as that usually ascribed to CaO. 1
Emission continuum from 19500 to 25000 cm^-1.
↳Hamada, 1931
A ¹Σ_u⁺	≤18963.7	≥136.66 2 Z	0.716₆ 3		≥0.058247 2	0.0003104 4		4.59E-08 5	≤3.8058	A ← X 6 V	18999.7 7 Z
A ¹Σ_u⁺	↳Weniger, 1966; missing citation
X ¹Σ_g⁺	0	64.92₈ Z	1.065₁	0.0025₉	0.046113	0.000702₈	-7.3₅E-06	9.5₂E-08 8	4.2773

Notes

The B_v values quoted by Kovalenok and Sokolov, 1967 are of the same order as those for CaO.

Vibrational numbering unknown.

ω_ex_e= -0.0037₄(v+1/2)³ - 0.000080(v+1/2)⁴.

α_v= -[2.15(v+1/2)² + 0.097[v+1/2)³]E-6.

H_e= 1.9kE-14.

RKR curves and Franck-Condon factors Balfour and Whitlock, 1975.

Energy of the lowest observed vibrational level relative to X ¹Σ_g⁺ (v=0).

D_v= +[0.043₁(v+1/2)+0.0010₇(v+1/2)²]E-7; H_e = -1.4E-13 Balfour and Whitlock, 1975 and higher order constants Balfour and Whitlock, 1975.

Extrapolation of the vibrational levels in X ¹Σ_g⁺.

References

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Kovalenok and Sokolov, 1967
Kovalenok, G.V.; Sokolov, V.A., Quantum vibration analysis of the orange band of Ca₂, Izv. Sib. Otd. Akad. Nauk SSSR, Ser. Khim. Nauk, 1967, 4, 118. [all data]

Hamada, 1931
Hamada, H., III. On the molecular spectra of mercury, zinc, cadmium, magnesium, and thallium, Philos. Mag., 1931, 12, 50. [all data]

Weniger, 1966
Weniger, S., L'elargissement de la raie 4226,73 Å(4₃² ^λS_o-4_P¹ ¹P₁^o) de ca i dans les spectres de laboratoire et dans les etoiles d M in Proceedings IAU Colloquim on Late-Type Stars, Trieste, M. Hack, ed(s)., 1966, 25-34. [all data]

Balfour and Whitlock, 1975
Balfour, W.J.; Whitlock, R.F., The visible absorption spectrum of diatomic calcium, Can. J. Phys., 1975, 53, 472. [all data]

Notes

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Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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