Doubly-excited state resonances of the helium-like nitrogen ion N5+ near then=3 threshold of N6+

1994 ◽  
Vol 31 (1-2) ◽  
pp. 37-40 ◽  
Author(s):  
N. A. B. Faye ◽  
A. Wagu�
Author(s):  
Sofia Canola ◽  
Yasi Dai ◽  
Fabrizia Negri

Conjugated singlet ground state diradicals have received remarkable attention owing to their potential applications in optoelectronic devices. A distinctive character of these systems is the location of the double exciton state, a low lying excited state dominated by the doubly excited H,H→L,L configuration, which may influence optical and other photophysical properties. In this contribution we investigate this specific excited state, for a series of recently synthesized conjugated diradicals, employing time dependent density functional theory based on the unrestricted parallel spin reference configuration in the spin-flip formulation (SF-TDDFT) and standard TD calculations based on the unrestricted antiparallel spin reference configuration (TDUDFT). The quality of the computed results is assessed considering diradical and multiradical descriptors and the excited state wavefunction composition.


2009 ◽  
Vol 467 (4-6) ◽  
pp. 260-264 ◽  
Author(s):  
M.-A. Gaveau ◽  
J.-M. Mestdagh ◽  
T. Bouissou ◽  
G. Durand ◽  
M.-C. Heitz ◽  
...  
Keyword(s):  

Author(s):  
Lennart Aufleger ◽  
Patrick Friebel ◽  
Patrick Rupprecht ◽  
Alexander Magunia ◽  
Thomas Ding ◽  
...  

Abstract We study the interaction of intense extreme ultraviolet (XUV) light with the 2s2p doubly excited state in helium. In addition to previously understood energy-level and phase shifts, high XUV intensities may lead to other absorption line shape distortions. Here, we report on experimental transient-absorption spectroscopy results on the 2s2p line width modification in helium in intense stochastic XUV fields. A few-level model simulation is realized to investigate the origins of this effect. We find that the line shape broadening is connected to the strong coupling of the ground state to the 2s2p doubly excited state which is embedded in the ionization continuum. As the broadening takes place for intensities lower than for other strong-coupling processes, e.g. observing asymmetry changes of the absorption profile, this signature can be identified already in an intermediate intensity regime. These findings are in general relevant for resonant inner shell transitions in nonlinear experiments with XUV and x-ray photon energies at high intensity.


1976 ◽  
Vol 7 (18) ◽  
pp. no-no
Author(s):  
JAROSLAV KOLC ◽  
JOHN W. DOWNING ◽  
ANTHONY P. MANZARA ◽  
JOSEF MICHL
Keyword(s):  

1992 ◽  
Vol 70 (2) ◽  
pp. 309-313 ◽  
Author(s):  
Yoshiko Sakai ◽  
Eisaku Miyoshi ◽  
Tosinobu Anno

Multireference singly and doubly excited CI (MRSDCI) calculations are performed on the NaI molecule by using a model potential method. The potential energy curves of the ground and first excited 1∑+ states are generated over a wide range of internuclear distance R. The curves yield the avoided crossing, which is expected to arise by the mixing of the ionic and covalent configurations, and thus the curve of the first excited state shows a shallow minimum. The geometrical parameters, dipole moment, and dissociation energy are calculated. The agreement of those with the experimental results is satisfactory. Keywords: NaI, MRSDCI calculation, model potential method, potential curve, excited state.


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