The 4550 Å band system of glyoxal. IV. Vibration–rotational analyses for 11 bands of 13C2H2O2 and determination of molecular geometries

1977 ◽  
Vol 55 (5) ◽  
pp. 390-395 ◽  
Author(s):  
F. W. Birss ◽  
D. B. Braund ◽  
A. R. H. Cole ◽  
R. Engleman Jr. ◽  
A. A. Green ◽  
...  
Keyword(s):  
Excited State ◽  
Electron Diffraction ◽  
Excellent Agreement ◽  
Ground State ◽  
Band System ◽  
Vibrational Frequencies ◽  
Geometrical Parameters ◽  
Rotational Constants ◽  
Vibrational Constants

Rotational analyses have been carried out for 11 bands of the [Formula: see text](π*–n) system of 13C2H2O2 in absorption. Approximately 12 000 lines have been assigned, and rotational and vibrational constants have been evaluated. The following vibrational frequencies have been determined: ν2′ = 1365.17 cm−1, ν4′ = 918.81 cm−1, ν5′ = 502.48 cm−1, ν7′ = 229.40 cm−1, ν7″ = 124.61 cm−1Using the rotational constants for C2H2O2, C2HDO2, C2D2O2, 13C2H2O2, and C2H218O2, the following geometrical parameters have been evaluated: in the Ã1Au excited state, r0(CH) = 1.115 ± 0.010 Å, r0(CO) = 1.252 ± 0.016 Å, r0(CC) = 1.460 ± 0.025 Å, [Formula: see text], [Formula: see text]; in the [Formula: see text] ground state, r0(CH) = 1.109 ± 0.008 Å, r0(CO) = 1.202 ± 0.012 Å, r0(CC) = 1.527 ± 0.017 Å, [Formula: see text], [Formula: see text]. The ground state parameters are in excellent agreement with earlier electron diffraction results.

ULTRAVIOLET SPECTRA OF LiH AND LiD

1957 ◽  
Vol 35 (10) ◽  
pp. 1204-1214 ◽  
Author(s):  
R. Velasco
Keyword(s):  
Excited State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
High Dispersion ◽  
Dissociation Energies ◽  
Near Ultraviolet ◽  
Path Lengths ◽  
Vibrational Constants ◽  
Π State

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.

ROTATIONAL ANALYSIS OF THE β BANDS OF PHOSPHORUS MONOXIDE

1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh
Keyword(s):  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Fine Structures ◽  
Π State

The fine structures of three of the β bands of PO which occur near 3200 Å have been analyzed. The analysis shows that the upper state of this band system is a 2Σ and not a 2Π state as previously believed. The rotational constants of both electronic states have been determined and it is found that the ground state constants, previously determined from the γ bands, are incorrect.

Vibrational Analysis of the 2800 Å Band System of para-Dibromobenzene

1972 ◽  
Vol 50 (12) ◽  
pp. 1402-1408 ◽  
Author(s):  
S. M. Japar
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Ground State ◽  
Band System ◽  
Vibrational Analysis ◽  
Type A ◽  
Strong Type ◽  
Type B ◽  
Sequence Structure ◽  
Extensive Sequence

The 2800 Å band system of p-dibromobenzene has been photographed under high resolution and an extended vibrational analysis has been carried out. The analysis is not inconsistent with the assignment of the system to a 1B2u ← 1Ag transition, by analogy with other p-dihalogenated benzenes. The observed spectrum can be explained in terms of a number of strong type-B vibronic bands and a considerably smaller number of type-A vibronic bands. The extensive sequence structure is adequately accounted for, and can be related to observations on other halogenated benzene molecules. Thirteen ground state and nine excited state fundamental vibrational frequencies have been assigned.

The analysis of a 2 A 1 - 2 B 1 electronic band system of the AsH 2 and AsD 2 radicals

1968 ◽  
Vol 305 (1481) ◽  
pp. 271-290 ◽  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Flash Photolysis ◽  
Band System ◽  
Valence Angle ◽  
Electronic Transitions ◽  
Doublet State ◽  
Electronic Band ◽  
Asymmetric Rotor ◽  
Asymmetric Top

Two new band systems have been observed in absorption following flash photolysis of AsH 3 and AsD 3 , and are assigned to 2 A 1 - 2 B 1 electronic transitions of AsH 2 and AsD 2 . The origins of both systems are at 19905 cm -1 . The bands have the complex rotational structure associated with an asymmetric rotor. Rotational analyses have been carried out for three bands of the AsH 2 spectrum, leading to the following molecular parameters: ground state, r" 0 = 1.518 Å valence angle = 90° 44'; excited state, r' 0 = 1.48 Å, valence angle = 123° 0'. The parameters associated with rotation about the a inertial axis increase rapidly with increase in v' 2 . The spectrum shows doublet splittings of up to 41 cm -1 , and the excited state furnishes the first example of a doublet state of an asymmetric top molecule which shows substantial departures from Hund’s case ( b ).

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.

The electronic spectrum of F2

1976 ◽  
Vol 54 (13) ◽  
pp. 1343-1359 ◽  
Author(s):  
E. A. Colbourn ◽  
M. Dagenais ◽  
A. E. Douglas ◽  
J. W. Raymonda
Keyword(s):  
Absorption Spectrum ◽  
Ground State ◽  
Band System ◽  
Rydberg States ◽  
Rotational Analysis ◽  
Interaction Energies ◽  
Rydberg Series ◽  
Rotational Constants ◽  
Vibrational Levels ◽  
Ionic States

The absorption spectrum of F2 in the 780–1020 Å range has been photographed at sufficient resolution to allow a rotational analysis of many bands. A large number of vibrational levels of three ionic states have been observed and their rotational constants determined. Many perturbations in the rotational structure caused by the interaction between the three states have been investigated and the interaction energies determined. The rotational and vibrational structures of a few Rydberg states have also been analyzed in detail but no Rydberg series have been identified. The difficulties in assigning the observed states are discussed. A 1Σu+ – X1Σg+ emission band system has been observed in the 1100 Å region. An analysis of the bands of this system has allowed us to determine the term values and rotational constants of all the vibrational levels of the ground state with ν ≤ 22. The dissociation energy, D0(F2), is found to be greater than 12 830 and is estimated to be 12 920 ± 50 cm−1.

A Pulsed Photoacoustic Microcalorimeter for the Detection of Upper Excited-State Processes and Intersystem Crossing Yields

1989 ◽  
Vol 43 (5) ◽  
pp. 826-833 ◽  
Author(s):  
Daniel Lynch ◽  
John F. Endicott
Keyword(s):  
Excited State ◽  
Excited States ◽  
Excellent Agreement ◽  
Piezoelectric Transducer ◽  
Detection System ◽  
High Energy ◽  
Intersystem Crossing ◽  
Photoacoustic Detection ◽  
Deconvolution Techniques

A photoacoustic detection system is described that has excellent linearity and limits of detection, and which is simple to implement. This system has been applied to the determination of intersystem crossing yields, φisc, of a series of Cr(NN)33+ complexes. The results are in excellent agreement with the literature values for two of these complexes. Results for two other complexes determined that there are long-lived (τ < 15 ns) upper excited states or other high-energy species produced that prevent rapid relaxation to the lowest energy excited state of these complexes. Without the need to resort to deconvolution techniques, this method can be used on systems that have rapid relaxation (τ < 1 ns) of the upper excited states and lifetimes <5 μs for the lowest energy excited state, with the application of a 5 MHz piezoelectric transducer.

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