Systematics of band-spectral constants. Part V. Interrelation of dissociation energy and equilibrium internuclear distance of di-atoms in ground states

1940 ◽  
Vol 35 ◽  
pp. 370 ◽  
Author(s):  
C. H. Douglas Clark
Keyword(s):  
Dissociation Energy ◽  
Internuclear Distance ◽  
Ground States ◽  
Equilibrium Internuclear Distance

A new predissociated 2Σ+ state of the BeCl molecule

1977 ◽  
Vol 55 (6) ◽  
pp. 582-588 ◽  
Author(s):  
M. Carleer ◽  
B. Burtin ◽  
R. Colin
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Dissociation Energy ◽  
Intensity Distribution ◽  
Internuclear Distance ◽  
Ground State ◽  
Thermochemical Data ◽  
Molecular Constants ◽  
Equilibrium Internuclear Distance ◽  
A Value

Ten bands belonging to a new B2Σ+–X2Σ+ system of the BeCl molecule have been discovered in emission between 1990 and 2175 Å. The bands of both isotopes Be35Cl and Be37Cl have been photographed at high resolution and the most intense ones have been rotationally analyzed. Only three levels of the excited state have been observed and they present vibrational and rotational perturbations. The principal molecular constants of the new B2Σ+ state of Be35Cl are: v00 = 48 827.6, ΔG1/2 = 925.5, ΔG3/2 = 1212.7, Be = 0.7751, De = 3.5 × 10−6 cm−1, and the equilibrium internuclear distance is 1.7422 Å. The unusual intensity distribution in the bands can be tentatively interpreted as the result of an inverse predissociation which leads to a value of D″0 = 27 800 ± 500 cm−1 (3.45 ± 0.06 eV) for the dissociation energy of the ground state of the BeCl molecule. This value is at variance with thermochemical data.

Theoretical Study of the Dissociation and Isomerization of NCS

2003 ◽  
Vol 217 (3) ◽  
pp. 255-264 ◽  
Author(s):  
M. Diehr ◽  
G. Chambaud ◽  
H.-J. Werner
Keyword(s):  
Excited States ◽  
Dissociation Energy ◽  
Ground State ◽  
Spectroscopic Data ◽  
Large Scale ◽  
Theoretical Study ◽  
Ground States ◽  
Electronic Ground State ◽  
Barrier Heights ◽  
Electronic Ground

AbstractLarge scale MRCI calculations have been performed to study the electronic ground state and low-lying excited states of the NCS molecule and its isomers. The isomer CNS is found to be stable and linear. It lies 1.29 eV higher in energy than NCS, while CSN has a much higher energy and is unstable. The dissociation energy of the NCS isomer has been calculated to be 4.25 eV. The isomerization paths between the 2Π ground states of both isomers have been mapped by CASSCF and MRCI calculations. The barriers for the NCS → CNS isomerization in 2A′ and 2A″ symmetry have cyclic forms and the barrier heights have been calculated to be 2.71 eV and 2.44 eV, respectively (MRCI). For both isomers, the collinear dissociation paths to the (diatomic + atom) fragments have been investigated by CASSCF calculations. Spectroscopic data are given for the X2Π ground state and for the A2Σ+ state of CNS. The results are compared with the valence isoelectronic system NCO.

Rotational analysis of the A-X and B-X systems of AuBe and AuMg

1965 ◽  
Vol 287 (1409) ◽  
pp. 240-258 ◽  
Keyword(s):  
Dissociation Energy ◽  
Thermal Emission ◽  
Ground States ◽  
Rotational Analysis ◽  
Kcal Mole ◽  
Electronic Band ◽  
Vibrational Levels ◽  
Two Systems

Electronic band systems of the gaseous molecules AuBe and AuMg may be observed in thermal emission or in absorption at temperatures around 2000 °C. The rotational analysis of bands of two systems of each molecule has been carried out. The ground states are 2 Σ + states, correlating with Au 2 S 1/2 and Be 1 S 0 or Mg 1 S 0 . The upper states are Ω = 1/2 states derived from Au 2 D 2 1/2 and Be 1 S 0 or Mg 1 S 0 . All the upper states show appreciable Ω-doubling. The following constants (cm-1) have been obtained: state Too A(7j Be 10® a re (A-) (i) AuBe Bh 18956-68 622-28 0-47944 4-34 2-0199 A$ 17194-88 647-57 0-49264 4-63 1-9927 X*E+ 0 600-63 0-46074 4-00 2-0605 (ii) AuMg B 19507-52 — [0-14043] — [2-3695] Ah 18409-05 — [0-14201] — [2-3562] X 2E+ 0 306-10 0-13214 0-73 2-4427 Figures in parentheses refer to v = 0. The vibrational levels in the upper states of AuBe converge rather rapidly, but only a rough estimate of the dissociation energy can be obtained: this is D 0 0 AuBe) ~ 67 kcal/mole.

ON THE DISSOCIATION OF PbF AND BiF MOLECULES

1965 ◽  
Vol 43 (5) ◽  
pp. 829-835 ◽  
Author(s):  
Ran B. Singh ◽  
D. K. Rai
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Potential Function ◽  
Dissociation Energy ◽  
Ground States ◽  
Potential Energy Curves ◽  
Empirical Potential ◽  
Dissociation Energies

True potential energy curves have been calculated for the A and X states of BiF and PbF molecules using the Rydberg–Klein–Rees (R.K.R.) method as modified by Vanderslice et al. It has already been shown that by fitting an empirical potential function to the actual potential (R.K.R.) curve of a state we can obtain an idea of the correct dissociation energy of the molecule in that particular state. The three-parameter Lippincott function has been used for this purpose. The resulting dissociation energies for the ground states of PbF and BiF are (2.4 ± 0.2) eV and (2.60 ± 0.2) eV respectively. In PbF a large number of band systems are known, two of which show predissociation in the upper excited state. It has been found possible to account for both of these predissociations in PbF as being due to the A state of the molecule.

The electronic spectrum of the AlAu molecule

1963 ◽  
Vol 273 (1352) ◽  
pp. 133-144 ◽  
Keyword(s):  
High Resolution ◽  
Electronic Spectrum ◽  
Dissociation Energy ◽  
Internuclear Distance ◽  
Ground State ◽  
Single Bond ◽  
Kcal Mole

The spectrum of AlAu has been photographed both in emission and in absorption with high resolution in the region 3800 to 6500 A. Rotational analyses have been carried out for six bands of the A -X system and for two bands of the C-X system. The internuclear distance r e in the ground state is found to be 2·338 Å, considerably shorter than predicted from tables of single-bond covalent radii. The dissociation energy in the ground state, D ¨ 0 , is estimated to be 64 kcal/mole.

Polarizability and internuclear distance in the hydrogen molecule and molecule-ion

1950 ◽  
Vol 203 (1074) ◽  
pp. 364-374 ◽  
Keyword(s):  
Wave Function ◽  
Raman Scattering ◽  
Internuclear Distance ◽  
Hydrogen Molecule ◽  
Wave Functions ◽  
Fair Agreement ◽  
Equilibrium Internuclear Distance ◽  
Internuclear Distances

The polarizability of the hydrogen molecule-ion has been calculated for a range of internuclear distances, using various types of wave-functions. It is concluded that the values obtained for the polarizability are relatively insensitive to the choice of wave-function. Similar calculations have been made for the hydrogen molecule, using an LCAO wave-function. The value obtained for the polarizability at the equilibrium internuclear distance is in fair agreement with experiment and with the results of earlier calculations. The predicted variation of polarizability with internuclear distance agrees approximately with that deduced previously from the refractivities of hydrogen and deuterium, but is greater than that derived from the observed intnesities of Rayleigh and Raman scattering.

Sign in / Sign up

Export Citation Format

Share Document