The studies of BaO were important pioneering experiments showing the power of microwave/optical double resonance methods. We shall describe a number of significant applications of these methods later in this chapter. [Pg.884]

Although 3IIoe can mix with many excited 1E+ states, mixing with the X1E+ state introduces a novel feature, namely, the appearance of permanent electric dipole moments as well as transition moments in the intensity borrowing model. For 3II in the case (a) limit (A > 21/2BJ), [Pg.408]

Figure 1. Adiabatic potential surfaces (a) for the linear E x e case and (b) for a 1E state with linear Jahn-Teller coupling and spin-orbit coupling to a 2 A state. |

An alternative method to obtain the nonadiabatic wavefunctions [Eq. (4.1.1)], the coupled equation approach, will be discussed in Section 4.4.3. It has been used for an excited 1E+ state of H2 and the error is now smaller than 1 cm-1 for the lowest vibrational levels (Yu and Dressier, 1994). Multichannel Quantum Defect Theory (MQDT), discussed in Chapter 8, has also been used with success for the same problem by Ross and Jungen (1994). Finally, a variational numerical approach (Wolniewicz, 1996), gives very good results for H2. [Pg.236]

The total parity of the final state is equal to the parity of the ionic level times the parity of the electron partial wave (which is even for even l and odd for odd l). For example, for a transition from a 1E+ molecular state to a 2II ion state, starting from J" = 4 (e-level, + parity), the J+ = 7/2 rotational level of the ion has two components one e-level (— parity), one /-level (+ parity) (see Fig. 8.16). The selection rule for allowed one-photon transitions is H— —. Consequently, for the transition into the ion e-level, the partial wave of the ejected electron is l = 0 (s) for the transition into the ionic /-level, the partial wave of the ejected electron is l = 1 (p). Equation (8.1.8a), with S -1- = 1/2, is satisfied for these l values. [Pg.556]

The 3E and p-complex structures resemble each other because both consist of one unit of spin or electronic angular momentum (S or L) coupled to the nuclear rotation (R). However, since fj, operates exclusively on electron spatial coordinates, any resemblance between the rotational-branch intensity patterns for 3S —1E+ and p-complex —1E+ transitions would seem to be coincidental. A 3E —1E+ transition will look exactly like a p-complex —1E+ transition if, in addition to satisfying Eqs. (6.3.47), the cr-orbital of the 1E+ state is predominantly of scr united atom character. Then the transition moment ratio will be [Pg.399]

The spin-spin interaction is zero for E states with S < The other selection rules for the Hss operator are g g or u u, but the selection rule E1 1 E is opposite to that for the spin-orbit operator, which is E1 1 E. Note, however, that the spin-spin interaction is zero between triplet and singlet states if both of them are E states (for example, a 3Eq state has only / levels and the universal selection rule for perturbations is e / thus 1E 3E Hss perturbations are e/ / forbidden see the end of Section 3.4.5). [Pg.196]

The total width, T, is the sum of partial widths, which can be calculated but not observed separately. Only the total width can be observed experimentally. This width does not depend on whether the line is observed in an absorption, photoionization, photodissociation, or emission spectrum because the width (or the lifetime) is characteristic of a given state (or resonance). In contrast, the peak profile can have different line shapes in different channels the line profile, q, is dependent on the excitation and decay mode (see Sections 7.9 and 8.9). For predissociation into H+CT, the transition moment from the X1E+ state to the 3n (or 3E+) predissociating state is zero, consequently q = oo and the lineshape is Lorentzian. In contrast, the ratio of the two transition moments for transitions to the XE+ continuum of the X2n state and to the (A2E+)1E+ Rydberg states leads to q 0 for the autoionized peaks (see Fig. 8.26) (Lefebvre-Brion and [Pg.606]

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