Theoretical Spectroscopy on Small Molecules: Ab initio Investigations of Vibronic Structure, Spin-Orbit Splittings and Magnetic Hyperfine Effects in the Electronic Spectra of Triatomic Molecules

1995 ◽  
pp. 261-356 ◽  
Author(s):  
M. Perić ◽  
B. Engels ◽  
S. D. Peyerimhoff
Keyword(s):  
Ab Initio ◽  
Small Molecules ◽  
Electronic Spectra ◽  
Magnetic Hyperfine ◽  
Spin Orbit ◽  
Vibronic Structure ◽  
Triatomic Molecules ◽  
Theoretical Spectroscopy

Magnetic hyperfine interactions in the electronic spectra of diatomic molecules I. The rotational structure of absorption bands of gaseous BiO

1967 ◽  
Vol 300 (1463) ◽  
pp. 469-486 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Ground State ◽  
Electronic Spectra ◽  
Hyperfine Interactions ◽  
Magnetic Hyperfine ◽  
Doppler Width ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Absorption Bands ◽  
Single Level

The absorption spectrum of gaseous BiO has been photographed at a resolution of about 300000. The ground state X 1 , is the Ω = 1/2 component of a 2 π state in which the spin-orbit coupling must be very large, ~ 1 eV. The doubling in X 1 is large, and for v = 0, ∆ v cd ~ 0.187 ( J + 1/2). Structure of 16 bands has been analysed: the bands arise from transitions from X 1 to four states, A 2 π 1/2 , B ( 4 Ʃ - ) Ω = 1/2, C ( 2 ∆ 3/2 ) Ω = 3/2 and D ( 2 π 1/2 ) Ω = 1/2. They show a number of unusual features, not least of which is the fact that, with the exception of D ─ X 1 , the lines in the regions analysed, 251/2 ≼ J ≼ 90 1/2, have a half-width, ∆ v 1/2 ~ 0.25 cm -1 , apparently independent of J , and far larger than the Doppler width. It is shown that this effect arises from unresolved nuclear magnetic hyperfine doubling of the levels in the ground state. The rotational levels in the single level of state D to be observed are predissociated both at high and at low J , but for intermediate values comparatively sharp lines are observed, by a partial cancellation of the h. f. s. between states D and X 1 . The case b designation of state B is 4 Ʃ - , but the structure of the bands show that the transition is better described as Ω = 1/2 — Ω = 1/2, in which the perpendicular transition moment is somewhat larger than the parallel one.

Spin-orbit vibronic coupling in Π3 states of linear triatomic molecules

2007 ◽  
Vol 126 (13) ◽  
pp. 134312 ◽  
Author(s):  
Sabyashachi Mishra ◽  
Leonid V. Poluyanov ◽  
Wolfgang Domcke
Keyword(s):  
Vibronic Coupling ◽  
Spin Orbit ◽  
Triatomic Molecules
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