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Beryllium monohydride


Constants of diatomic molecules

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

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

Data collected through September, 1976

Symbols used in the table of constants
SymbolMeaning
State electronic state and / or symmetry symbol
Te minimum electronic energy (cm-1)
ωe vibrational constant – first term (cm-1)
ωexe vibrational constant – second term (cm-1)
ωeye vibrational constant – third term (cm-1)
Be rotational constant in equilibrium position (cm-1)
αe rotational constant – first term (cm-1)
γe rotation-vibration interaction constant (cm-1)
De centrifugal distortion constant (cm-1)
βe rotational constant – first term, centrifugal force (cm-1)
re internuclear distance (Å)
Trans. observed transition(s) corresponding to electronic state
ν00 position of 0-0 band (units noted in table)
Diatomic constants for 9BeH
StateTeomegaeomegaexeomegaeyeBealphaegammaeDebetaereTrans.nu00
G 2Pi 58711 405.3 Z 22.7  5.02 1 2 -0.556 -0.04 [18E-4] 3  1.925 G larrow X R 57886.2 Z
missing citation
F 2Sigma+ (4psigma) (56606) (2153) 4   [10.576] 5   [8.0E-4] 3  [1.326] F larrow X 56661.24 Z
missing citation
E 2Sigma+ (4ssigma) (54134) (1970) 4   [10.578] 6   [22.4E-4] 3  [1.326] E larrow X 54097.6 Z
missing citation
D 2Sigma+ (54000) 7          D larrow X 54050
missing citation
StateTeomegaeomegaexeomegaeyeBealphaegammaeDebetaereTrans.nu00
D 2Pi (3d) (54000) 7          D larrow X 54050
missing citation
D 2Delta (54000) 7          D larrow X 54050
missing citation
B 2Pi (3ppi) 50882 8 2265.94 Z 71.52  10.8495 9 10 2 0.1016 -0.1324 [10.35E-4] 3  1.3092 B lrarrow X VR 50976.17 Z
Watson and Humphreys, 1937; missing citation
A 2Pir (2ppi) 20033.19 11 2088.58 12 Z 40.14 -0.47 10.4567 13 0.3222 -0.0042 10.41E-4 14  1.3336 A lrarrow X 15 V 16 20045.81 12 Z
missing citation; Olsson, 1932; missing citation
StateTeomegaeomegaexeomegaeyeBealphaegammaeDebetaereTrans.nu00
X 2Sigma+ (2psigma) 0 2060.78 12 Z 36.31 -0.38 10.3164 17 0.3030 -0.0027 10.221E-4 18  1.3426 19  
Knight, Brom, et al., 1972
20           

Notes

1Lambda-type doubling; for details see Colin and De Greef, 1975. R and P lines involving v'=0 and 1 are twice as broad as the corresponding Q lines. v=2 is strongly perturbed.
2 Colin and De Greef, 1975 suggest that the B and G states result from an avoided 2Pi - 2Pi crossing, the former (B 2Pi) having a double minimum potential curve with a potential maximum corresponding to Te = 56950 cm-1 at r=1.94 .
3For additional Dv and higher order constants see Colin and De Greef, 1975.
4Using isotope relations.
5perturbation at low N. Higher vibrational levels are probably predissociated.
6missing note
7Strong absorption, complex structure.
8 Colin and De Greef, 1975 give 50888.57, without explanation. A~0.
9Lambda-type doubling, Deltavef(v=0) = +0.217N(N+l).
10The BlrarrowX bands (v' leq 2, and fragments of the 3-3 band of BeD) consist of Q branches only except the 0-0 band which, in absorption, has P and R branches showing a marked broadening increasing with N. The predissociation mechanism involves both the unobserved 3psigma state and the first excited 2Sigma+ state which is unstable except at very large r values; for details see Lefebvbre-Brion and Colin, 1977. The Q branch lines of BeH (BeD) break off at N'=31, 24 missing citation, 14 missing citation, Meyer and Rosmus, 1975 in v'=0,1,2,3, respectively, owing to the presence of a maximum in the B 2Pi potential curve; see 2 . Two additional levels of BeH, very likely belonging to B 2Pi but called B' 2Pi (v', v'+1) in Colin and De Greef, 1975, are situated above the potential energy maximum in B 2Pi: B' 2Pi(v'+1), Te=[58435.8], B=6.01, D=187E-4 B' 2Pi(v'), Te=[58284.8], B=8.34, D=0.0129 and higher order constants. Transitions to these levels from X 2Sigma+ consist of Q branches only, breaking off at N'=14 in v'+1.
11Taking into account the usually neglected contributions Y'00 and Y"00 to the zero point energies of A and X. A(spin-orbit) = +2.1; for an ab initio calculation see Walker and Richards, 1969.
12Derived Horne and Colin, 1972 from pure vibronic energy separations which differ from the origins normally referred to in these tables.
13Lambda-type doubling, Deltavef(v=0) = +0.0141N(N+l) -...; higher order constants in Horne and Colin, 1972. Theoretical calculations Hinkley, Hall, et al., 1972 Hinkley, Walker, et al., 1972.
14Higher order constants in Horne and Colin, 1972.
15Theoretical absorption oscillator strengths Henneker and Popkie, 1971, Popkie, 1971.
16Reversal of shading in some of the bands.
17Spin splitting constant gamma0 = +0.005.
18Higher order constants in Horne and Colin, 1972.
19ESR sp. 24
20For theoretical calculations see references in Horne and Colin, 1972 Bagus, Moser, et al., 1973 Meyer and Rosmus, 1975.
21From the predissociation by rotation Colin and De Greef, 1975 in the B' 2Pi, v'+1 level (see 10), assuming dissociation into Be(1P) + H(2S). The experimental X 2Sigma+ well depth of 2.161 eV is in good agreement with the calculated values De=2.115 eV Bagus, Moser, et al., 1973 and De = 2.15 eV Meyer and Rosmus, 1975.
22From the observation of Rydberg states in the absorption spectrum, and from ab initio calculations for BeH and BeH+; see Colin, DeGreef, et al., 1974.
23Line width increases with decreasing N; the first lines are not observed.
24In Ar matrix at 4 K Knight, Brom, et al., 1972.

References

Go To: Top, Constants of diatomic molecules, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Watson and Humphreys, 1937
Watson, W.W.; Humphreys, R.F., Ultraviolet spectra of BeH and BeH+, Phys. Rev., 1937, 52, 318. [all data]

Olsson, 1932
Olsson, E., Das bandenspektrum des berylliumhydrides, Z. Phys., 1932, 73, 732. [all data]

Knight, Brom, et al., 1972
Knight, L.B., Jr.; Brom, J.M., Jr.; Weltner, W., Jr., Hyperfine interaction and chemical bonding in the BeH molecule, J. Chem. Phys., 1972, 56, 1152. [all data]

Colin and De Greef, 1975
Colin, R.; De Greef, D., The absorption spectrum of the BeH and BeD molecules in the vacuum ultraviolet, Can. J. Phys., 1975, 53, 2142. [all data]

Lefebvbre-Brion and Colin, 1977
Lefebvbre-Brion, H.; Colin, R., Anomalous isotope effects in indirect predissociations, J. Mol. Spectrosc., 1977, 65, 33. [all data]

Meyer and Rosmus, 1975
Meyer, W.; Rosmus, P., PNO-Cl and CEPA studies of electron correlation effects. III. Spectroscopic constants and dipole moment functions for the ground states of the first-row and second-row diatomic hydrides, J. Chem. Phys., 1975, 63, 2356. [all data]

Walker and Richards, 1969
Walker, T.E.H.; Richards, W.G., Calculation of spin-orbit coupling constants in diatomic molecules from Hartree-Fock wave functions, Phys. Rev., 1969, 177, 100. [all data]

Horne and Colin, 1972
Horne, R.; Colin, R., The A2«PI»-X2«SIGMA»+ band system of BeH and BeD in absorption, Bull. Soc. Chim. Belg., 1972, 81, 93. [all data]

Hinkley, Hall, et al., 1972
Hinkley, R.K.; Hall, J.A.; Walker, T.E.H.; Richards, W.G., «LAMBDA» doubling in 2«PI» states of diatomic molecules, J. Phys. B:, 1972, 5, 204. [all data]

Hinkley, Walker, et al., 1972
Hinkley, R.K.; Walker, T.E.H.; Richards, W.G., The variation of «LAMBDA» doubling with rotational quantum number BeH and BeD, J. Phys. B:, 1972, 5, 2016. [all data]

Henneker and Popkie, 1971
Henneker, W.H.; Popkie, H.E., Theoretical electronic transition probabilities in diatomic molecules. I. Hydrides, J. Chem. Phys., 1971, 54, 1763. [all data]

Popkie, 1971
Popkie, H.E., Theoretical electronic transition probabilities in diatomic molecules. III. BeH and MgH (A2«PI»-X2«SIGMA»+) systems, J. Chem. Phys., 1971, 54, 4597. [all data]

Bagus, Moser, et al., 1973
Bagus, P.S.; Moser, C.M.; Goethals, P.; Verhaegen, G., Accurate ab initio calculation of the BeH molecule. I. The X2«SIGMA»+ and A2«PI» states, J. Chem. Phys., 1973, 58, 1886. [all data]

Colin, DeGreef, et al., 1974
Colin, R.; DeGreef, D.; Goethals, P.; Verhaegen, G., The ionization potential of the BeH molecule, Chem. Phys. Lett., 1974, 25, 70. [all data]


Notes

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