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Magnesium 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 March, 1977

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 24MgH
StateTeomegaeomegaexeomegaeyeBealphaegammaeDebetaereTrans.nu00
Unidentified line structure at 42570 cm-1 [em. and abs., Guntsch, 1934 Guntsch, 1935 Turner and Harris, 1937 Guntsch, 1939] and 43180 - 43520 cm-1 [abs., Khan, 1962].
I (2Pi)     [5.96]   [2E-4]  [1.710] I larrow X V 47997.6 Z
Khan, 1962
H (2Sigma+) 1           H larrow X R 47543 (Z)
Khan, 1962
G (2Sigma+) 2           G larrow X V 46082 (Z)
Khan, 1962
StateTeomegaeomegaexeomegaeyeBealphaegammaeDebetaereTrans.nu00
D 2Sigma- (42065) (1630) 3   [6.296] 4   [3.8E-4]  [1.664] D rarrow A V 22861.5 5
Guntsch, 1937; Guntsch, 1939
C 2Pi(r) (41164) 6 [1623.4] Z   6.161 7 0.144  3.0E-4  1.682 C rarrow A 21956.5 5
Pearse, 1929; Guntsch, 1934; Guntsch, 1937, 2; Guntsch, 1939
           C lrarrow X V 41235.9 Z
missing citation; Guntsch, 1935; Grundstrom, 1936; Guntsch, 1937, 2; Turner and Harris, 1937; Guntsch, 1939; missing citation
E 2Sigma+ (35568) [1444.8] Z 8  6.23 0.30 9  [3.3E-4] 10  1.673 E larrow X VR 35550.6 Z
Khan, 1961; missing citation; Balfour and Cartwright, 1975
StateTeomegaeomegaexeomegaeyeBealphaegammaeDebetaereTrans.nu00
B' 2Sigma+ 22410.5 828.0 Z 11.6 11  [2.596] 12  1.2E-4 0.13E-4 2.597 B' rarrow X R 22081.9 Z
Balfour and Cartwright, 1975; Balfour and Cartwright, 1976
A 2Pir 19226.8 13 1598.17 Z 31.085 14 -0.633 6.1913 0.1931 15 0.0005 3.60E-4 16  1.6778 A lrarrow X 17 18 V 19278.4 5
Guntsch, 1937; Guntsch, 1939; Balfour, 1970; Balfour, 1970, 2; Balfour and Cartwright, 1976, 2
X 2Sigma+ 0 1495.20 Z 31.889 19 0.384 5.8257 0.1859 20  3.44E-4 16  1.7297 21  
Knight and Weltner, 1971

Notes

1R shaded band with head at 2100 Å.
2V shaded band with head at 2172 Å.
3Estimated from w2 = 4B3/D and from the observed isotope shift of the 0-0 band.
4Spin doubling. |gamma| = 0.01.
5Average of the two subband origins Guntsch, 1939.
6A0 = (+)3.7; Balfour, 1970, 2 gives -3.7, but his arguments are not conclusive.
7The P and R branches of the CrarrowX, 0-0 band break off above N' = 10; bands with v'>0 have Q branches only. The predissociation is caused by B' 2Sigma+; see Balfour and Cartwright, 1975.
8DeltaG(3/2)= 1490. The v=2 level was formerly believed to be v=0 of a new 2Sigma state (B 2Sigma+), see Grundstrom, 1936, Grundstrom, 1936, 2, Guntsch, 1938, Guntsch, 1939. Similarly, Khan, 1961 assigned the 1-0 band as 0-0 of a new system FlarrowX.
9B2 = 5.448; see 8. Transitions to v=1 are discrete but those to v=2 are diffuse indicating that the state causing the predissociation [B' 2Sigma+, see Balfour and Cartwright, 1975] crosses the E state potential curve between v=1 and 2. Emissions from v=2 has been observed at high pressure.
10D1 = 4.0E-4; D2 = 2.71E-4; H2 = +8.6E-8; (see 8).
11The equilibrium constants in Balfour and Cartwright, 1976 do not reproduce the observed intervals, probably owing to an error in omegaeze. De ~ 10900 cm-1 Balfour and Cartwright, 1976
12Bv(v=1,2,3,4...9) = 2.605, 2.618, 2.608, 2.592, ... 2.419; Be = 2.585, but the higher order constants of Balfour and Cartwright, 1976 do no reproduce their data. Small perturbations by A 2Pi. RKR potential curve Balfour and Cartwright, 1976. See also Sink, Bandrauk, et al., 1976.
13A0= +35.3 Balfour, 1970, 2
14These constants (for vleq3) have been recalculated from the three DeltaG values obtained by Balfour and Cartwright, 1976, 2; the equilibrium constants determined by Balfour and Cartwright, 1976, 2 do not reproduce their data. De ~ 14200 cm-1 Balfour and Cartwright, 1976, 2.
15Small perturbations by B' 2Sigma+.
16Dv increases rapidly with v.
17Oscillator strength f00= 0.257 [see Balfour and Cartwright, 1976, 2 and references given there], much larger than the earlier experimental value of Main, Carlson, et al., 1967.
18 Balfour, 1970 has measured the 0-0 and 0-1 bnads of 25MgH and 26MgH; see also Branch, 1970, Boyer, 1971.
19omegaeze= -0.113 Balfour and Cartwright, 1976, 2; De0 ~ 11700 cm-1 Balfour and Cartwright, 1976, 2.
20+0.00393(v+1/2)2 - 0.00123(v+1/2)3. The last term was not reported by Balfour and Cartwright, 1976, 2 but must be included for a satisfactory fit to their data (v=0...6).
21ESR sp. 23
22From extrapolations of the vibrational levels in X, A and B'. Close agreement with the theoretical value of Meyer and Rosmus, 1975, D0 = 1.25 eV.
23In Ar matrices at 4K.

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.

Guntsch, 1934
Guntsch, A., Uber das bandenspektrum des magnesiumhydrids, Z. Phys., 1934, 87, 312. [all data]

Guntsch, 1935
Guntsch, A., Uber das ultraviolette bandenspektrum des magnesiumhydrids und magnesiumdeutrids, Z. Phys., 1935, 93, 534. [all data]

Turner and Harris, 1937
Turner, L.A.; Harris, W.T., The ultraviolet bands of magnesium hydride, Phys. Rev., 1937, 52, 626. [all data]

Guntsch, 1939
Guntsch, Dissertation, Stockholm, 1939, 1. [all data]

Khan, 1962
Khan, M.A., MgH bands at 2172, 2100 and 2088 Å and MgD bands at 2172, 2358 and 2364 A, Proc. Phys. Soc. London, 1962, 80, 209. [all data]

Guntsch, 1937
Guntsch, A., Neue untersuchungen uber das bandenspektrum des magnesiumhydrids, Z. Phys., 1937, 104, 584. [all data]

Pearse, 1929
Pearse, R.W.B., The ultra-violet spectrum of magnesium hydride. 1. The band at «lambda»2430, Proc. R. Soc. London A, 1929, 122, 442. [all data]

Guntsch, 1937, 2
Guntsch, A., Uber einige neue banden des magnesiumhydrids, Z. Phys., 1937, 107, 420. [all data]

Grundstrom, 1936
Grundstrom, Dissertation, Stockholm, 1936, 0. [all data]

Khan, 1961
Khan, M.A., MgH and MgD bands at 2819 Å and 2702 Å, Proc. Phys. Soc. London, 1961, 77, 1133. [all data]

Balfour and Cartwright, 1975
Balfour, W.J.; Cartwright, H.M., Low-lying electronic states of magnesium hydride, Chem. Phys. Lett., 1975, 32, 82. [all data]

Balfour and Cartwright, 1976
Balfour, W.J.; Cartwright, H.M., The B'2«SIGMA»+ --> X2«SIGMA»+ systems of MgH and MgD, Can. J. Phys., 1976, 54, 1898. [all data]

Balfour, 1970
Balfour, W.J., The A2«PI» --> X2«SIGMA»+ systems of 24MgH, 25MgH, and 26MgH, Astrophys. J., 1970, 162, 1031. [all data]

Balfour, 1970, 2
Balfour, W.J., The electronic spectrum of magnesium hydride and magnesium deuteride, J. Phys. B:, 1970, 3, 1749. [all data]

Balfour and Cartwright, 1976, 2
Balfour, W.J.; Cartwright, H.M., The A2«PI»-X2«SIGMA»+ system and dissociation energy of magnesiun hydride, Astron. Astrophys. Suppl. Ser., 1976, 26, 389. [all data]

Knight and Weltner, 1971
Knight, L.B., Jr.; Weltner, W., Jr., Hyperfine interaction and chemical bonding in MgH, CaH, SrH, and BaH molecules, J. Chem. Phys., 1971, 54, 3875. [all data]

Grundstrom, 1936, 2
Grundstrom, B., Absorption spectrum of magnesium hydride in the ultra-violet, Nature (London), 1936, 131, 108. [all data]

Guntsch, 1938
Guntsch, A., Druckeffekt in der magnesiumhydridbande bei «lambda»2590 Å, Z. Phys., 1938, 110, 549. [all data]

Sink, Bandrauk, et al., 1976
Sink, M.L.; Bandrauk, A.D.; Henneker, W.H.; Lefebvre-Brion, H.; Raseev, G., Theoretical study of the low-lying electronic states of MgH, Chem. Phys. Lett., 1976, 39, 505. [all data]

Main, Carlson, et al., 1967
Main, R.P.; Carlson, D.J.; DuPuis, R.A., Measurement of oscillator strengths of the MgO(B1«SIGMA»+ - X1«SIGMA»+) and MgH(A2«PI» - X2«SIGMA»+) band systems, J. Quant. Spectrosc. Radiat. Transfer, 1967, 7, 805. [all data]

Branch, 1970
Branch, D., Isotopes of magnesium in the sun, Astrophys. J., 1970, 159, 39. [all data]

Boyer, 1971
Boyer, R., Isotopic lines of the MgH molecule, Astron. Astrophys., 1971, 12, 464. [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]


Notes

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