ABSORPTION SPECTRA OF ETHYLENE AND ETHYLENE-d4 IN THE VACUUM ULTRAVIOLET. II

1956 ◽  
Vol 34 (7) ◽  
pp. 643-652 ◽  
Author(s):  
P. G. Wilkinson
Keyword(s):  
Absorption Spectra ◽  
Vacuum Ultraviolet ◽  
Stable Equilibrium ◽  
Equilibrium Configuration ◽  
Rydberg States ◽  
Torsional Oscillator ◽  
Potential Barriers ◽  
First Order ◽  
Stretching Vibration ◽  
Vibrational Constants

The absorption spectra of ethylene and ethylene-d4 have been investigated in the 1300 Å to 1500 Å region using the first order of a 21-ft. vacuum grating spectrograph. Vibrational constants for the v2(ag) stretching vibration and the v4(au) twisting vibration have been determined for each of the observed five Rydberg states. The torsional oscillator–rotator treatment has been applied to the observed twisting data, and potential barriers hindering free rotation of 500 to 1200 cm−1 were obtained. It is concluded that the stable equilibrium configuration of the Rydberg states is not of D2h symmetry but is probably bent or staggered.

ABSORPTION SPECTRA OF BENZENE AND BENZENE-d6 IN THE VACUUM ULTRAVIOLET

1956 ◽  
Vol 34 (6) ◽  
pp. 596-615 ◽  
Author(s):  
P. G. Wilkinson
Keyword(s):  
Absorption Spectra ◽  
Vacuum Ultraviolet ◽  
Stable Equilibrium ◽  
Normal Incidence ◽  
Rydberg Series ◽  
First Order ◽  
Jahn Teller ◽  
Vibrational Bands ◽  
Vibrational Constants ◽  
Rydberg Transitions

The absorption spectra of benzene and benzene-d6 have been photographed from 1300 Å to 1850 Å in the first order of a 21-ft. normal incidence vacuum spectrograph. The band analysis resulted in the identification of four Rydberg series (over one hundred vibrational bands) in each molecule, converging to ionization potentials of 9.247 ev. (benzene) and 9.251 ev. (benzene-d6). Progressions of the ν2, ν18, and ν20 vibrations are associated with most of the 31 observed Rydberg transitions, and vibrational constants are tabulated for each. The strong intensity and the unusual length of the upper state ν18 (e2g) progression in comparison with the ν2(a1g) progression are interpreted in terms of the Jahn–Teller theorem, and it is concluded that the stable equilibrium nuclear configuration in the Rydberg states is of D2h symmetry.

The absorption spectrum of Cl2 in the vacuum ultraviolet

1981 ◽  
Vol 59 (6) ◽  
pp. 835-840 ◽  
Author(s):  
A. E. Douglas
Keyword(s):  
Absorption Spectrum ◽  
Vacuum Ultraviolet ◽  
Band System ◽  
Rydberg States ◽  
Ultraviolet Region ◽  
Isotopic Molecule ◽  
Vacuum Ultraviolet Region ◽  
Vibrational Constants ◽  
Made In

The absorption spectrum of Cl2 in the vacuum ultraviolet region has been photographed with sufficient resolution to allow rotational analyses of many bands. The separated isotopic molecule 35Cl2 and cooled absorption cells were used to simplify the spectrum. A band system associated with an ionic state has been observed in the 1330–1450 Å range. Many large perturbations in the system prevent the determination of the usual rotational and vibrational constants. Some progress has been made in the analyses of a few bands associated with Rydberg states.

New electronic transitions of the C2 molecule in absorption in the vacuum ultraviolet region

1969 ◽  
Vol 47 (24) ◽  
pp. 2735-2743 ◽  
Author(s):  
G. Herzberg ◽  
A. Lagerqvist ◽  
C. Malmberg
Keyword(s):  
Ground State ◽  
Vacuum Ultraviolet ◽  
Rydberg States ◽  
The Other ◽  
Electronic Transitions ◽  
Lower State ◽  
Ultraviolet Region ◽  
New States ◽  
Vacuum Ultraviolet Region ◽  
Vibrational Constants

Three new electronic transitions of the C2 molecule have been observed in absorption in the region 1300–1450 Å. The system of shortest wavelength is readily identified as a 1Πu–1Σg+ transition; the lower state is the ground state X1Σg+ of the molecule. The other two systems arise by absorption from the low-lying a3Πu state; the upper states are new 3Σg− and 3Δg states. Rotational and vibrational constants of the three new states have been determined. The new states are Rydberg states. Their correlation to the separated atoms is briefly discussed.

The electronic spectra of HCl and HF

1979 ◽  
Vol 57 (10) ◽  
pp. 1650-1661 ◽  
Author(s):  
A. E. Douglas ◽  
F. R. Greening
Keyword(s):  
Absorption Spectra ◽  
Electronic Spectra ◽  
Vacuum Ultraviolet ◽  
Rydberg States ◽  
Spectral Lines ◽  
High Dispersion ◽  
Ultraviolet Region ◽  
Vibrational Levels ◽  
Vacuum Ultraviolet Region ◽  
Ionization Limit

The absorption spectra of HCl and HF have been photographed at high dispersion in the vacuum ultraviolet region. In the HCl spectrum, many new band systems have been identified and 18 vibrational levels of the ionic B1Σ state have been observed. The B1Σ state is found to interact strongly with the Rydberg states. Although many bands have been analysed, much of the HCl spectrum remains unassigned. Analyses of bands associated with the lowest discrete 1Π and 3Π states of HF are presented together with the analyses of two 1Π–X1Σ band systems which lie between the first and second ionization limit. The spectrum of HF is very complex and little of it has been analysed even though the spectral lines are sharp and well resolved. The theoretical problems in understanding the spectra of HCl and HF are discussed.

Vacuum ultraviolet photodissociation dynamics of OCS + hv → CO(1Σ+) + S(1S0) via the E and F Rydberg states

2021 ◽  
Author(s):  
Caining Ling ◽  
Hong Liao ◽  
Daofu Yuan ◽  
Wentao Chen ◽  
Yuxin Tan ◽  
...  
Keyword(s):  
Vacuum Ultraviolet ◽  
Rydberg States ◽  
The State ◽  
Ultraviolet Photodissociation ◽  
Stretching Vibration

The state-resolved photodissociation of the CO(1Σ+) + S(1S0) photoproduct channel, formed by vacuum ultraviolet photoexcitation of OCS to a progression of the symmetric stretching vibration (ν1') in the E and...

Photocolouration of 2,4,4,6-Tetraaryl-4H-pyrans and Their Heteroanalogues: Importance of Hypervalent Photoisomers

1995 ◽  
Vol 60 (10) ◽  
pp. 1621-1633 ◽  
Author(s):  
Stanislav Böhm ◽  
Mojmír Adamec ◽  
Stanislav Nešpůrek ◽  
Josef Kuthan
Keyword(s):  
Reaction Kinetics ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Theoretical Data ◽  
Order Reaction ◽  
Bleaching Process ◽  
First Order ◽  
Photodegradation Products ◽  
Hypervalent Molecules

Molecular geometries of 2,4,4,6-tetraphenyl-4H-pyran (Ia), 4,4-(biphenyl-2,2e-diyl)-2,6-diphenyl-4H-pyran (Ib) and their heterocyclic isomers II-V were optimized by the PM3 method and used for the calculation of electronic absorption spectra by the CNDO/S-CI procedure. Comparison of the theoretical data with experimental UV-VIS absorption spectra made possible to select hypervalent molecules IIIa, IIIb, IVa and IVb being responsible for the photocolouration of 4H-pyrans Ia, Ib, while compounds Va, Vb, VI and VII come into account as possible photodegradation products. The bleaching process of the UV illuminated compound Ia is analyzed in terms of dispersive first-order reaction kinetics.

High resolution spectrum of GdO

1976 ◽  
Vol 54 (24) ◽  
pp. 2429-2434 ◽  
Author(s):  
B. R. Yadav ◽  
S. B. Rai ◽  
D. K. Rai
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Visible Emission ◽  
High Resolution Spectrum ◽  
First Order ◽  
Isotopic Shifts ◽  
Vibrational Constants ◽  
Dc Arc

The visible emission spectrum of the GdO molecule has been produced in a DC arc source and has been photographed in the first order of a 10.6 m grating spectrograph. Bands are shown to have a six-headed structure and improved vibrational constants have been obtained in this study. Isotopic shifts have been calculated for the various isotopic molecules. Tentative suggestions regarding the nature of the transition have been made.

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