76
3 Diatomic Molecules
the examples of HCl and CO in Table 3.8. In this table, the r e structure calculated
from Y 01 , (3.56), (3.76), i.e., neglecting the breakdown of the Born–Oppenheimer
approximation is also given. Although the effect of the breakdown is not constant,
it shows that it is not sensible to determine a structure with a precision higher than
about 0.007 pm (median absolute deviation) when this breakdown is neglected. For
the sake of completeness, it has to be remembered that the accuracy of the final
structure also depends on the accuracy of the Planck constant and of the atomic
masses. However, these constants are now highly accurate and the effect of their
uncertainty is generally negligible. Nevertheless, tiny differences may be observed
in some cases. For instance, the equilibrium bond length of
194 Pt
32 S is 203.98221 pm
when calculated with (3.56) using the constants tabulated in Gordy and Cook (1984)
whereas it is 203.98284 pm when calculated using the most recent constants (Cook
and Gerry 2004).
References
Angeli I, Marinova KP (2013) Table of experimental nuclear ground state charge radii: an update.
At Data Nucl Data Tables 99:69–95
Authier N, Bagland N, Le Floch A (1993) The 1992 evaluation of mass-independent Dunham
parameters for the ground state of CO. J Mol Spectrosc 160:590–592
Badger M (1934) A Relation between internuclear distances and bond force constants. J Chem Phys
2:128–131
Barrow GM (1962) Introduction to molecular spectroscopy. McGraw-Hill, New York
Bellini M, De Natale P, Inguscio M, Varberg TD, Brown JM (1995) Precise experimental test of
models for the breakdown of the Born–Oppenheimer separation: the rotational spectra of isotopic
variants of lithium hydride. Phys Rev A 52:1954–1960
Bogey M, Demuynck C, Destombes JL (1982) Millimeter and submillimeter wave spectrum of
CS 1 in high vibrational states: Isotopic dependence of Dunham coefficients. J Mol Spectrosc
95:35–42
Brown JM, Carrington A (2003) Rotational spectroscopy of diatomic molecules. Cambridge
University Press
Cazzoli G, Cludi L, Degli Esposti C, Dore L (1989) The millimeter and submillimeter-wave
spectrum of boron monofluoride: equilibrium structure. J Mol Spectrosc 134:159–167
Cooke SA, Gerry MCL (2004) Internuclear distance and effects of born-oppenheimer breakdown
for PtS, determined from its pure rotational spectrum. J Chem Phys 121:3486–3494
Cooke SA, Gerry MCL, Chong DP (2004) The calculation of field shift effects in the rotational spectra of heavy metal-containing diatomic molecules using density functional theory:
comparison with experiment for the Tl-halides and Pb-chalcogenides. Chem Phys 298:205–212
Costain CC (1958) Determination of molecular structures from ground state rotational constants. J
Chem Phys 29:864–874
Coxon JA, Hajigeorgiou PG (1991) Isotopic dependence of Born-Oppenheimer breakdown effects
in diatomic hydrides: the X1 + states of HI/DI and HBr/DBr. J Mol Spectrosc 150:1–27
Coxon JA, Hajigeorgiou PG (2015) Improved direct potential fit analyses for the ground electronic
states of the hydrogen halides: HF/DF/TF, HCl/DCl/TCl, HBr/DBr/TBr and HI/DI/TI. J Quant
Spectrosc Radiat Transf 151:133–154
Dunham JL (1932) The energy levels of a rotating vibrator. Phys Rev 41:721–731
Gauss J, Ruud K, Helgaker T (1996) Perturbation-dependent atomic orbitals for the calculation of
spin-rotation constants and rotational g tensors. J Chem Phys 105:2804–2812
3 Diatomic Molecules
the examples of HCl and CO in Table 3.8. In this table, the r e structure calculated
from Y 01 , (3.56), (3.76), i.e., neglecting the breakdown of the Born–Oppenheimer
approximation is also given. Although the effect of the breakdown is not constant,
it shows that it is not sensible to determine a structure with a precision higher than
about 0.007 pm (median absolute deviation) when this breakdown is neglected. For
the sake of completeness, it has to be remembered that the accuracy of the final
structure also depends on the accuracy of the Planck constant and of the atomic
masses. However, these constants are now highly accurate and the effect of their
uncertainty is generally negligible. Nevertheless, tiny differences may be observed
in some cases. For instance, the equilibrium bond length of
194 Pt
32 S is 203.98221 pm
when calculated with (3.56) using the constants tabulated in Gordy and Cook (1984)
whereas it is 203.98284 pm when calculated using the most recent constants (Cook
and Gerry 2004).
References
Angeli I, Marinova KP (2013) Table of experimental nuclear ground state charge radii: an update.
At Data Nucl Data Tables 99:69–95
Authier N, Bagland N, Le Floch A (1993) The 1992 evaluation of mass-independent Dunham
parameters for the ground state of CO. J Mol Spectrosc 160:590–592
Badger M (1934) A Relation between internuclear distances and bond force constants. J Chem Phys
2:128–131
Barrow GM (1962) Introduction to molecular spectroscopy. McGraw-Hill, New York
Bellini M, De Natale P, Inguscio M, Varberg TD, Brown JM (1995) Precise experimental test of
models for the breakdown of the Born–Oppenheimer separation: the rotational spectra of isotopic
variants of lithium hydride. Phys Rev A 52:1954–1960
Bogey M, Demuynck C, Destombes JL (1982) Millimeter and submillimeter wave spectrum of
CS 1 in high vibrational states: Isotopic dependence of Dunham coefficients. J Mol Spectrosc
95:35–42
Brown JM, Carrington A (2003) Rotational spectroscopy of diatomic molecules. Cambridge
University Press
Cazzoli G, Cludi L, Degli Esposti C, Dore L (1989) The millimeter and submillimeter-wave
spectrum of boron monofluoride: equilibrium structure. J Mol Spectrosc 134:159–167
Cooke SA, Gerry MCL (2004) Internuclear distance and effects of born-oppenheimer breakdown
for PtS, determined from its pure rotational spectrum. J Chem Phys 121:3486–3494
Cooke SA, Gerry MCL, Chong DP (2004) The calculation of field shift effects in the rotational spectra of heavy metal-containing diatomic molecules using density functional theory:
comparison with experiment for the Tl-halides and Pb-chalcogenides. Chem Phys 298:205–212
Costain CC (1958) Determination of molecular structures from ground state rotational constants. J
Chem Phys 29:864–874
Coxon JA, Hajigeorgiou PG (1991) Isotopic dependence of Born-Oppenheimer breakdown effects
in diatomic hydrides: the X1 + states of HI/DI and HBr/DBr. J Mol Spectrosc 150:1–27
Coxon JA, Hajigeorgiou PG (2015) Improved direct potential fit analyses for the ground electronic
states of the hydrogen halides: HF/DF/TF, HCl/DCl/TCl, HBr/DBr/TBr and HI/DI/TI. J Quant
Spectrosc Radiat Transf 151:133–154
Dunham JL (1932) The energy levels of a rotating vibrator. Phys Rev 41:721–731
Gauss J, Ruud K, Helgaker T (1996) Perturbation-dependent atomic orbitals for the calculation of
spin-rotation constants and rotational g tensors. J Chem Phys 105:2804–2812