HCr

Formula: CrH
Molecular weight: 53.0040
CAS Registry Number: 13966-79-5
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Constants of diatomic molecules

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

Data collected through December, 1974

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 ⁽⁵²⁾CrH
State	T_e	ω_e	ω_ex_e	B_e	α_e	D_e	r_e	Trans.	ν₀₀
								(30386)
↳Kleman and Liljeqvist, 1955; Smith, 1973
B (⁶Π) 1								B ↔ (X)	(27181)
B (⁶Π) 1	↳Gaydon and Pearse, 1937; Kleman and Liljeqvist, 1955; Kleman and Uhler, 1959; O'Connor, 1969; Smith, 1973
A ⁶Σ⁽⁺⁾	(11611)	[1479.4] Z	21.₅ H	5.337 2	0.13₁	[0.000247] 3	1.787	A → X R	11552.29 Z
A ⁶Σ⁽⁺⁾	↳Kleman and Liljeqvist, 1955; missing citation; missing citation
X ⁶Σ⁽⁺⁾	0	[1581.₂] H	(32)	6.220 4	0.179	[0.000347] 5	1.655₇

Notes

Complex V shaded band in the region 26975 - 27930 cm^-1. 7

Spin splitting constants Kleman and Uhler, 1959, O'Connor, 1967 γ₀ = 1.20, λ₀= 0.14. Perturbations in both v=0 and v=1 may be caused by a state ⁸Σ state Kleman and Uhler, 1959.

H₀= +0.7E-8; D₁= 2.3₆E-4.

Spin splitting constants γ0 ~ 0.1, λ₀ ~ 0.03 Kleman and Uhler, 1959, O'Connor, 1967.

H₀ = +1.0E-8; D₁ = 3.43E-4.

Described as rather diffuse by Smith, 1973.

The weakness of the emission at low pressures, and the stronger appearance of the corresponding deuteride system suggest predissociation of the upper state through a potential hill O'Connor, 1969.

Spin splitting constants γ₀ = 0.64, λ₀ = 0.28. Several perturbations.

H₀ = +0.1₀E-8.

Spin splitting constants γ₀ = 0.02₃, λ₀ = 0.03.

H₀ = +0.07E-8.

References

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Kleman and Liljeqvist, 1955
Kleman, B.; Liljeqvist, B., On the band spectrum of CrH, Ark. Fys., 1955, 9, 345. [all data]

Smith, 1973
Smith, R.E., Diatomic hydride and deuteride spectra of the second row transition metals, Proc. R. Soc. London A, 1973, 332, 113. [all data]

Gaydon and Pearse, 1937
Gaydon, A.G.; Pearse, R.W.B., Band spectrum of chromium hydride, CrH, Nature (London), 1937, 140, 110. [all data]

Kleman and Uhler, 1959
Kleman, B.; Uhler, U., A ⁶Σ-⁶Σ transition in CrH, Can. J. Phys., 1959, 37, 537. [all data]

O'Connor, 1969
O'Connor, S., A predissociation in the chromium hydride molecule, J. Phys. B:, 1969, 2, 541. [all data]

O'Connor, 1967
O'Connor, S., The infrared spectrum of CrH and CrD, Proc. R. Ir. Acad. Sect. A:, 1967, 65, 95-113. [all data]

Notes

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Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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