Ab initio R-matrix/multichannel quantum defect theory study of nitric oxide

Abstract

Ab initio R-matrix techniques are combined with multi-channel quantum defect theory to determine the properties of arbitrarily highly excited electronic states of nitric oxide. Results are obtained for l = 0-4 channels associated with the four lowest NO+ target channels, namely 1Σ+, 3Σ+, 3Π and 3Δ. Energy and bond length variations of the quantum defect functions for all target states are reported. Certain small surface amplitude R-matrix poles also serve to determine the energies of valence states. Diabatic potential curves for Rydberg states converging to the 1Σ+ and 3Σ+ target states and for the valence states are presented. Systematic jumps in the pσ quantum defects for all target states as the bond length increases beyond R = 2.5 au are attributed to Rydbergization of the antibonding 2pσ* molecular orbital.

Dissociation and predissociation in the ns 1B1 and np1A2 series of H2O

“…In the absence of other information, this latter term was taken as G 12 (0, 0) = G + (000)−ω with a width at half height of 6700 cm −1 , which may be compared with the experimental values of 60500 cm −1 and 7200cm −1 [30]. The width is therefore well reproduced and the main contribution to the discrepancy in the peak positions probably arises from the assumption of an energy independent quantum defect function, because ab initio estimates [31] of the vertical excitation energies between the 3s and 4s potential surfaces indicates a decrease in the quantum defect from µ = 1.31 to 1.21, which is well in line with a calculated jump in the s quantum defect of NO by 0.1 units, attributable to core polarization effects at energies where the d channels open, an effect that is very well established for NO [32,33]. The variations between the predissociation linewidths in Table 2 are the main focus of the paper.…”

Excitation and characterization of long-lived hydrogenic Rydberg states of nitric oxide

“…The complete interpretation of the experimental data in Figure 8 requires the combination of multichannel quantum defect theory 29,66,67 or matrix diagonalization methods 26,27,29,30,68 , and a numerical treatment of the timeevolution of the excited state population in the stray electric fields, and 300 K blackbody radiation field in the apparatus 12,14 . However, to highlight the primary role played by near degeneracies between np(0) and nf(2) Rydberg states, which are accessible by electric dipole transitions from the A 2 Σ + intermediate state, and high-hydrogenic states in the work reported here, we consider a simple numerical model in which seven Rydberg series are included.…”

Time-, angle- and kinetic-energy-resolved photoelectron spectroscopy of highly excited states of NO

“…The marked result from figure 7(a) with the notation (J + 1/2) + for = 3/2 and (J + 1/2) − for = 1/2. help of the MQDO method and using the known quantum defects η λ [48,54], formula (15) predicts β 2 = 0.88 for the ionization of the 4dδN 2 (v = 0) state. This is in good agreement with our experimentally determined value of 0.95 ± 0.1.…”