Linear symmetric molecules

XeF2 is a colorless crystalline compound stable up to 500°C, m.p. -129°C, with considerable vapor pressure for solids—4.5 mmHg (20°C). It is a linear symmetrical molecule. The mean thermochemical energy of the Xe—F bond in XeF2 is 132kJ/mol,3 which is less than the F—F bond energy—157.3 kJ/mol.4... 

According to classical theory the vibrational motion of a polyatomic molecule can be represented as a superposition of 3N-6 harmonic modes in each of which the atoms move synchronously (i.e. in phase) with a definite frequency v. These normal modes are characterized by time-dependent normal coordinates which indicate, on a mass-weighted scale, the relative displacement of the atoms from their equilibrium positions (Wilson et al., 1955). Figure 2 shows the general shape of the normal coordinates for a non-linear symmetric molecule AB2. The... 

The model potential displayed in Figure 8.2 had originally been used by Kulander and Light (1980) to study, within the time-independent R-matrix formalism, the photodissociation of linear symmetric molecules like C02. It will become apparent below that in this and similar cases the time-dependent approach, which we shall pursue in this chapter, has some advantages over the time-independent picture. The motion of the ABA molecule can be treated either in terms of the hyperspherical coordinates defined in (7.33) or directly in terms of the bond distances Ri and i 2 The Hamiltonian for the linear molecule expressed in bond distances... 

In the gas phase, all MnX2 compounds are linear symmetrical molecules with zero dipole moment.346,353 In addition, dimers [Mn20x-X2)X2] have been detected for at least the chloride and bromide.353 Parallels with the alkyl (3) and amido (11) species are evident. 

Point Charge Model of XY2 Linear Symmetric Molecules.—It is possible to model the potential energy in a molecule usefully by more primitive models than those just discussed. We consider here some consequences of a point charge model employed by Ray and Parr.69 So that we can be more specific than in the previous section, let us consider briefly the ideas of their approach with reference to linear triatomic molecules of the symmetric type XY2. 

Carbon suboxide is a linear symmetric molecule in its ground state and is of considerable Interest from a variety of viewpoints. Its electronic structure, for example, has been subjected to considerable theoretical analysis because of the extensive delocalized IT network. Because its constituent atoms are doubly bonded C and 0, it is the source of intensely chemiluminescent flames with atomic oxygen which have been shown to result in inverted distributions in product CO. The molecule has also been proposed as (i) a product of photochemical reactions in the primitive earth atmosphere, (il) a constituent of the Venus atmosphere, and (iii) a possible explanation for the variety of colors associated with the Mars surface. 

Derive the value of the universal constant a in the expression Qr aa IT for the rotational partition function of any diatomic (or any linear) molecule I is the moment of inertia in e.g.s. units and T is the absolute temperature. Calculate the rotational partition function of carbon dioxide (a linear symmetrical molecule) at 25 C. 

Linear symmetrical molecules such as polyethylene, polytetrafluoroethy-lene, and other linear molecules with more complex backbones containing -(-COO-, and -(-CONH-)- groups, such as polyethers,... 

In this operator the Majorana term originates the off-diagonal elements in the basis (4.124). Such elements are very important for a linear symmetric molecule such as HCCH or DCCD. The purely local part of the Hamiltonian (4.126) has eigenvalues given by... 

In agreement with earlier theoretical work [18], the trimer ions are found to be most stable in the state of the linear symmetric molecule. The ground ( SJ) state is bound by 1.376 eV at R = 4.94 bohr (cf. Bdhmer and Peyerimhoff who get 1.35 eV at R = 4.95 bohr) the state is very weakly bound at long range and the other states arc essentially repulsive in character. The energies of the... 

The leading multipolar term for fluids of linear symmetrical molecules, like carbon dioxide, nitrogen, acetylene, etc, is the quadrupole-quadrupole potential (Gubbins Twu, 1978). An expansion of the Helmholtz free energy density in terms of the perturbed quadrupole-quadrupole potential with the Fade approximation was proposed by SteU et al. (1974) ... 

---