fluorine

Formula: F₂
Molecular weight: 37.9968064
IUPAC Standard InChI: InChI=1S/F2/c1-2
IUPAC Standard InChIKey: PXGOKWXKJXAPGV-UHFFFAOYSA-N
CAS Registry Number: 7782-41-4
Chemical structure:
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Constants of diatomic molecules

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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 ¹⁹F₂
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
Many strong absorption bands observed and partially analyzed up to 126000 cm^-1, heavily perturbed and not assigned. 1
↳missing citation
K ¹Π_u					[1.040] 2	3				[1.306]	K ← X V	11655.72 Z
K ¹Π_u	↳Gole and Margrave, 1972; missing citation
J ¹Π_u (⁴p σ)	116409	[1032.6] Z			[1.041]	3				[1.306]	J ← X V	116469.4 Z
J ¹Π_u (⁴p σ)	↳missing citation
I ¹Σ_u⁺ (⁴p π)	113841	[1108.92] Z	4		[0.8009]	5		[1.8E-6] 6		1.488₆	I → f R	17081.6 $I H
	↳missing citation; Stricker and Krauss, 1968; Colbourn, Dagenais, et al., 1976
											I → F R	20732 7 H
	↳missing citation; Stricker and Krauss, 1968; Colbourn, Dagenais, et al., 1976
											I ↔ X 8 R	113940.24 Z
	↳di Lonardo and Douglas, 1972; Gole and Margrave, 1972; missing citation
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
H ¹Π_u (³pσ)	105520.14	1088.19 Z	9.875		1.021 9	0.014				1.318	H ← X V	105606.27 Z
H ¹Π_u (³pσ)	↳Gole and Margrave, 1972; Colbourn, Dagenais, et al., 1976
h ³Π_1u (3pσ)	(104904)	(1100) 10			1.022 11	0.016				1.318	h ← X V	104998.7 Z
h ³Π_1u (3pσ)	↳Colbourn, Dagenais, et al., 1976
G ¹Σ_u⁺ (³pπ)	(104300) 12
G ¹Σ_u⁺ (³pπ)	↳Colbourn, Dagenais, et al., 1976
E (¹Σ_u⁺)	≤100912	[196.3] 13 Z	(0.96)		[0.194] 13					[3.02] 13	E ← X R	100555.₅ 13 Z
E (¹Σ_u⁺)	↳missing citation
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
D (¹Σ_u⁺)	≤98756	[221.6] 13 Z	(1.22)		[0.207] 13					[2.93] 13	D ← X R	98411.₉ 13 Z
D (¹Σ_u⁺)	↳missing citation
f (³Π_1g) (3sσ)	[97314] 14	14			[1.005] 14					[1.329] 14
C ¹Σ_u⁺	≤93499	[493.2] 15 Z			[0.484] 15					[1.91₅] 15	C ↔ X R	93290.4 15 Z
C ¹Σ_u⁺	↳missing citation
F ¹Π_g (3sσ)	93099	1133.34 16 H	9.17₃		1.047 16	0.012				1.302
A ¹Π_u 17											A ← X
A ¹Π_u 17	↳Steunenberg and Vogel, 1956; Rees, 1957
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 ³Π_0+u 19											a ← X 18
a ³Π_0+u 19	↳Steunenberg and Vogel, 1956; Rees, 1957
X ¹Σ_g⁺	0	916.64 Z	11.236 20	-0.113	0.89019	0.013847 21		3.3E-6		1.41193 22
	↳Andrychuk, 1951; Claassen, Selig, et al., 1969; Stricker and Hochenbleicher, 1973; Edwards, Good, et al., 1976
	Mol. beam magn. reson. 23
	↳Ozier, Crapo, et al., 1964
	Ab initio calc.
	↳Das and Wahl, 1972

Notes

The assignments to two Rydberg series by Gole and Margrave, 1972 are questioned by Colbourn, Dagenais, et al., 1976.

B_Q; B_PR = 1.034.

B₂ = 0.9916.

ΔG(3/2)=754.06, ΔG(5/2)=553.78, ΔG(7/2)=733.01; strongly perturbed, not certain whether one or two electronic states are involved.

B₁= 0.8129, B₂= 0.8980, B₃= 0.8946, B₄= 0.891; see 4.

D_v(v=1...4, E-6 cm^-1) = 4.0, 14.0, -2.6, -50.0

v" uncertain, see 16.

Four of the strongest absorption bands; in emission only bands with v=0 and 1 and very weakly v=2.

From Q branches, B_Q - B_PR ~ +0.004. v' = 0,1,2,3 analyzed, a weak and highly perturbed band at 911 (109770 cm^-1) may be 4-0.

Estimated from the 0-0 and 2-0 (v₀= 107069.4) bands.

From Q branches; B_Q - B_PR = +0.005. v=0 strongly perturbed.

Infrared from strong perturbation of the higher vibrational levels of C ¹Σ_u⁺.

(Deperturbed) constants determined from the lowest observed levels; vibrational numbering unknown. Only those levels which interact strongly with C ¹Σ_u⁺ have been found in absorption. It is possible that D and E are not two independent states.

From I →f Porter, 1968; vibrational numbering unknown. The assignments of Stricker and Krauss, 1968 suggest the existence of additional levels at 1058 below and 1044 cm^-1 above the single level reported by Porter, 1968.

Constants for the lowest observed level, vibrational numbering unknown (v=n). In absorption levels up to v = n+30 have been observed. Numerous perturbations by levels of D and E (interaction matrix elements ~ 10 cm^-1); a much stronger interaction with G affects levels having v «gte» n+25. For details see Table 5 of Colbourn, Dagenais, et al., 1976.

Vibrational numbering uncertain. Extensive perturbations. Strong predissociation leading to line broadening in I→F bands having v" = 1,2,4,5,6,8; bands with v"= 3,7 are sharp.

Continuous absorption with maximum at 35000 cm^-1.

The existence of the a ←X absorption becomes clear only after subtraction of the much stronger effect of the A←X absorption from the observed absorption intensities Rees, 1957. It is generally assumed that the ³Π_0+u state has a minimum but no discrete absorption or emission has been observed, see Nathans, 1950. Child and Bernstein, 1973 predict a dissociation energy D_e= 3300 cm^-1 and r_e= 1.9 for this state.

Continuous absorption with maximum at 25500 cm^-1.

These constants represent only the lowest nine levels (i.e. v≤8) Colbourn, Dagenais, et al., 1976. Levels have been observed up to v=22; this last level lies only 90 cm^-1 below the extrapolated limit.

+0.0001179(v+1/2)² - 0.000020₃(v+1/2)³, representing B₀....B₁₂.

Raman sp.

Rotational gyromagnetic ratio g_J = -0.120₈ μ_N (nuclear) spin-rotation and spin- spin interaction constants c = -157.3 kHz, d = 8.0 kHz.

From the observed vibrational levels of the ground state Colbourn, Dagenais, et al., 1976; the highest observed level (presumably the last stable level) is at 12830.38 cm^-1. Shock tube experiments of Blauer and Solomon, 1972 give the same value within ±0.05 eV; see also the earlier work of Barrow and Caunt, 1953, Stamper and Barrow, 1958, DeCorpo, Steiger, et al., 1970.

From photoionization Berkowitz, Chupka, et al., 1971. Photoelectron spectra Cornford, Frost, et al., 1971 give 15.70 eV.

The lower state vibrational numbering of this band is unknown, see 14.

References

Go To: Top, Constants of diatomic molecules, Notes

Gole and Margrave, 1972
Gole, J.L.; Margrave, J.L., The vacuum ultraviolet spectrum of molecular fluorine, J. Mol. Spectrosc., 1972, 43, 65. [all data]

Stricker and Krauss, 1968
Stricker, W.; Krauss, L., Die Bestimmung der Dissoziationsenergie des F₂-Molekuls und ein Beitrag zu seinem Bandenspektrum, Z. Naturforsch. A, 1968, 23, 486. [all data]

Colbourn, Dagenais, et al., 1976
Colbourn, E.A.; Dagenais, M.; Douglas, A.E.; Raymonda, J.W., The electronic spectrum of F₂, Can. J. Phys., 1976, 54, 1343. [all data]

di Lonardo and Douglas, 1972
di Lonardo, G.; Douglas, A.E., Electronic spectra of HF and F₂, J. Chem. Phys., 1972, 56, 5185. [all data]

Steunenberg and Vogel, 1956
Steunenberg, R.K.; Vogel, R.C., The absorption spectrum of fluorine, J. Am. Chem. Soc., 1956, 78, 901. [all data]

Rees, 1957
Rees, A.L.G., Erratum: Electronic spectrum and dissociation energy of fluorine, J. Chem. Phys., 1957, 27, 1424. [all data]

Andrychuk, 1951
Andrychuk, D., The Raman spectrum of fluorine, Can. J. Phys., 1951, 29, 151. [all data]

Claassen, Selig, et al., 1969
Claassen, H.H.; Selig, H.; Shamir, J., Raman apparatus using laser excitation and polarization measurements. Rotational spectrum of fluorine, Appl. Spectrosc., 1969, 23, 8. [all data]

Stricker and Hochenbleicher, 1973
Stricker, W.; Hochenbleicher, J.G., Das lasererregte Raman-Spektrum von gasformigem Fluor, Z. Naturforsch. A, 1973, 28, 27. [all data]

Edwards, Good, et al., 1976
Edwards, H.G.M.; Good, E.A.M.; Long, D.A., Pure rotational Raman spectrum of fluorine, J. Chem. Soc. Faraday Trans. 2, 1976, 72, 984-987. [all data]

Ozier, Crapo, et al., 1964
Ozier, I.; Crapo, L.M.; Cederberg, J.W.; Ramsey, N.F., Nuclear interactions and rotational moment of F₂, Phys. Rev. Lett., 1964, 13, 482. [all data]

Das and Wahl, 1972
Das, G.; Wahl, A.C., Theoretical study of the F₂ molecule using the method of optimized valence configurations, J. Chem. Phys., 1972, 56, 3532. [all data]

Porter, 1968
Porter, T.L., Emission spectrum of molecular fluorine, J. Chem. Phys., 1968, 48, 2071. [all data]

Nathans, 1950
Nathans, M.W., The absorption spectrum and the dissociation energy of fluorine, J. Chem. Phys., 1950, 18, 1122. [all data]

Child and Bernstein, 1973
Child, M.S.; Bernstein, R.B., Diatomic interhalogens: systematics and implications of spectroscopic interatomic potentials and curve crossings, J. Chem. Phys., 1973, 59, 5916. [all data]

Blauer and Solomon, 1972
Blauer, J.; Solomon, W., Shock tube calorimeter for the dissociation energy of fluorine, J. Chem. Phys., 1972, 57, 3587. [all data]

Barrow and Caunt, 1953
Barrow, R.F.; Caunt, A.D., The ultra-violet absorption spectra of some gaseous alkali-metal halides and the dissociation energy of fluorine, Proc. R. Soc. London A, 1953, 219, 120. [all data]

Stamper and Barrow, 1958
Stamper, J.G.; Barrow, R.F., The dissociation energy of fluorine, Trans. Faraday Soc., 1958, 54, 1592. [all data]

DeCorpo, Steiger, et al., 1970
DeCorpo, J.J.; Steiger, R.P.; Franklin, J.L.; Margrave, J.L., Dissociation energy of F₂, J. Chem. Phys., 1970, 53, 936. [all data]

Berkowitz, Chupka, et al., 1971
Berkowitz, J.; Chupka, W.A.; Guyon, P.M.; Holloway, J.H.; Spohr, R., Photoionization mass spectrometric study of F₂, HF, and DF, J. Chem. Phys., 1971, 54, 5165. [all data]

Cornford, Frost, et al., 1971
Cornford, A.B.; Frost, D.C.; McDowell, C.A.; Ragle, J.L.; Stenhouse, I.A., Photoelectron spectra of the halogens, J. Chem. Phys., 1971, 54, 2651. [all data]

Notes

Go To: Top, Constants of diatomic molecules, References

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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