Low-Lying Electronic States and Dissociation Energies of the Monochlorides of Cr, Mn, Fe, Co, and Ni

2008 ◽  
Vol 112 (17) ◽  
pp. 3813-3815 ◽  
Author(s):  
D. L. Hildenbrand
Keyword(s):  
Electronic States ◽  
Dissociation Energies

Potential Energy Surfaces

1996 ◽  
Author(s):  
Tomas Baer ◽  
William L. Hase
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Electronic State ◽  
Diatomic Molecule ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Electronic States ◽  
Dissociation Energies ◽  
State Potential ◽  
Energy Surfaces

Properties of potential energy surfaces are integral to understanding the dynamics of unimolecular reactions. As discussed in chapter 2, the concept of a potential energy surface arises from the Born-Oppenheimer approximation, which separates electronic motion from vibrational/rotational motion. Potential energy surfaces are calculated by solving Eq. (2.3) in chapter 2 at fixed values for the nuclear coordinates R. Solving this equation gives electronic energies Eie(R) at the configuration R for the different electronic states of the molecule. Combining Eie(R) with the nuclear repulsive potential energy VNN(R) gives the potential energy surface Vi(R) for electronic state i (Hirst, 1985). Each state is identified by its spin angular momentum and orbital symmetry. Since the electronic density between nuclei is different for each electronic state, each state has its own equilibrium geometry, sets of vibrational frequencies, and bond dissociation energies. To illustrate this effect, vibrational frequencies for the ground singlet state (S0) and first excited singlet state (S1) of H2CO are compared in table 3.1. For a diatomic molecule, potential energy surfaces only depend on the internuclear separation, so that a potential energy curve results instead of a surface. Possible potential energy curves for a diatomic molecule are depicted in figure 3.1. Of particular interest in this figure are the different equilibrium bond lengths and dissociation energies for the different electronic states. The lowest potential curve is referred to as the ground electronic state potential. The primary focus of this chapter is the ground electronic state potential energy surface. In the last section potential energy surfaces are considered for excited electronic states. A unimolecular reactant molecule consisting of N atoms has a multidimensional potential energy surface which depends on 3N-6 independent coordinates. For the smallest nondiatomic reactant, a triatomic molecule, the potential energy surface is four-dimensional (three independent coordinates plus the energy). Since it is difficult, if not impossible, to visualize surfaces with more than three dimensions, methods are used to reduce the dimensionality of the problem in portraying surfaces. In a graphical representation of a surface the potential energy is depicted as a function of two coordinates with constraints placed on the remaining 3N-8 coordinates.

Accurate vibrational energy spectra and dissociation energies of some diatomic electronic states

2008 ◽  
Vol 3 (4) ◽  
pp. 382-413 ◽  
Author(s):  
Wei-guo Sun ◽  
Xiu-ying Liu ◽  
Yu-jie Wang ◽  
Yan Zhan ◽  
Qun-chao Fan
Keyword(s):  
Vibrational Energy ◽  
Electronic States ◽  
Energy Spectra ◽  
Dissociation Energies

ULTRAVIOLET SPECTRA OF LiH AND LiD

1957 ◽  
Vol 35 (10) ◽  
pp. 1204-1214 ◽  
Author(s):  
R. Velasco
Keyword(s):  
Excited State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
High Dispersion ◽  
Dissociation Energies ◽  
Near Ultraviolet ◽  
Path Lengths ◽  
Vibrational Constants ◽  
Π State

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.

scholarly journals Full Vibrational Energy Spectra and Dissociation Energies for Some Electronic States of Diatomic Halogen Molecules

2009 ◽  
Vol 25 (01) ◽  
pp. 13-18
Author(s):  
QU Shuang-Shuang ◽  
◽  
SUN Wei-Guo ◽  
WANG Yu-Jie ◽  
FAN Qun-Chao
Keyword(s):  
Vibrational Energy ◽  
Electronic States ◽  
Energy Spectra ◽  
Dissociation Energies

Ab initio calculations of the XI molecules (X = Li, Na, K, Rb) with the ionicity and laser cooling analysis

2020 ◽  
Vol 98 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Israa Zeid ◽  
Rania Al Abdallah ◽  
Nayla El-Kork ◽  
Mahmoud Korek
Keyword(s):  
Dipole Moment ◽  
Ab Initio ◽  
Laser Cooling ◽  
Ground State ◽  
Bound States ◽  
Electronic States ◽  
Spectroscopic Constants ◽  
Ionic Character ◽  
Canonical Function ◽  
Dissociation Energies

For the alkali iodide molecules LiI, NaI, KI, and RbI, ab initio CASSCF/(MRCI+Q) calculations have been employed to investigate the adiabatic potential energy curves and the static dipole moment curves of the low-lying singlet and triplet electronic states in the representation 2S+1Λ(+/−). The spectroscopic constants Te, Re, ωe, Be, αe, the dipole moment μe, and the dissociation energies De have been computed for the bound states. Additionally, the percentage ionic character fionic around the equilibrium position of the ground state and the (2)1Σ+ state has been estimated. Using the canonical function approach, these calculations have been followed by a rovibrational calculation from which the rovibrational constants Ev, Bv, Dv, and the abscissas of the turning points Rmin and Rmax for the investigated bound states are calculated.

Green and orange band spectra of CaOH, CaOD and calcium oxide

1955 ◽  
Vol 231 (1187) ◽  
pp. 437-445 ◽  
Keyword(s):  
Water Vapour ◽  
Alkaline Earth ◽  
Electronic States ◽  
Vacuum Arc ◽  
Triplet States ◽  
Excitation Process ◽  
Stellar Spectra ◽  
Dissociation Energies ◽  
Large Dispersion ◽  
Band Spectra

The green and orange flame bands have also been obtained in a ‘vacuum’ arc in water vapour and heavy-water vapour. An isotope shift has been observed, supporting James & Sugden’s assignment of the flame bands to CaOH. Absence of additional bands from an arc in mixed H 2 O and D 2 O eliminates Ca(OH) 2 . The fine and gross structure of the CaOH and CaOD bands is described and discussed; the molecule is non-linear; the excitation process is believed to be thermal rather than chemiluminescent. These flame bands are not the same as the green and orange bands obtained with calcium salts in an arc in air. These latter are probably due to an oxide, but their structure is too complex for them to be due, as has been suggested, to transitions between singlet electronic states of CaO. It is possible that they may be due to transitions between triplet states of CaO, but under large dispersion the structure is so very complex that a polyatomic emitter appears more likely, and the dimer Ca 2 O 2 is favoured. The relevance of these results to determinations of the dissociation energies of alkaline earth oxides, to the use of the bands in spectro-chemical analysis and to the absence of CaO bands from stellar spectra is discussed.

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