Laser Ionisation Spectroscopy Of Formyl Fluoride

1996 ◽  
Vol 51 (7) ◽  
pp. 809-812
Author(s):  
Reiner P. Schmid ◽  
Harold Jones
Keyword(s):  
Electronic State ◽  
Vibrational Level ◽  
Rotational Structure ◽  
Vibronic Band

A vibronic band of formyl fluoride near 39,511 cm-1 has been observed using multiphoton ionisation spectroscopy. From the analysis of the partially resolved rotational structure, the rotational parameters of the (0, 2, 0, 0, 0, 0) vibrational level of an electronic state near 39,000 cm ~1 have been determined: A = 92.50(1.46) GHz and (B + C)/2 = 11.23(30) GHz. The term value was determined to be 39,510.93(30) cm-1 .

The absorption spectrum of the free SiH2 radical

1968 ◽  
Vol 46 (22) ◽  
pp. 2485-2490 ◽  
Author(s):  
I. Dubois
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Vibrational Level ◽  
Visible Region ◽  
Rotational Structure ◽  
Lower State ◽  
High Dispersion ◽  
Bending Vibration ◽  
Lower Electronic State

The absorption spectrum of SiH2 in the visible region has been photographed at high dispersion and the rotational structure of three bands has been analyzed. In the lower electronic state 1A1 the HSiH angle is 92° 5′ and the Si–H distance 1.516 Å, while in the upper state these parameters are 123° and 1.487 Å, respectively. The observed bands correspond to excitation of the bending vibration [Formula: see text] in the upper state. In the lower state, only one excited vibrational level, 010, has been observed, yielding [Formula: see text].

THE ABSORPTION SPECTRUM OF CF2

1967 ◽  
Vol 45 (7) ◽  
pp. 2355-2374 ◽  
Author(s):  
C. Weldon Mathews
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Vibrational Structure ◽  
Rotational Structure ◽  
Transition Moment ◽  
High Dispersion ◽  
Parallel Type

The absorption spectrum of CF2 in the 2 500 Å region has been photographed at high dispersion, and the rotational structure of a number of bands has been analyzed. The analysis of the well-resolved subbands establishes that these are perpendicular- rather than parallel-type bands, as previously assigned. Further analysis shows that the upper and lower electronic states are of 1B1 and 1A1symmetries respectively, corresponding to a transition moment that is perpendicular to the plane of the molecule. In the upper electronic state, r0(CF) = 1.32 Å and [Formula: see text], while in the ground state, r0(CF) = 1.300 Å and [Formula: see text]. An investigation of the vibrational structure of the band system has shown that the vibrational numbering in ν2′ must be increased by one unit from earlier assignments, thus placing the 000–000 band near 2 687 Å (37 220 cm−1). A search between 1 300 and 8 500 Å showed two new band systems near 1 350 and 1 500 Å which have been assigned tentatively to the CF2 molecule.

The A2Π–X2Σ+ system of MgCl

1987 ◽  
Vol 65 (12) ◽  
pp. 1594-1603 ◽  
Author(s):  
M. Singh ◽  
G. S. Ghodgaonkar ◽  
M. D. Saksena
Keyword(s):  
High Resolution ◽  
Structure Analysis ◽  
Vibrational Level ◽  
High Frequency ◽  
Low Frequency ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
The Common ◽  
Π State

The A2Π–X2Σ+ system of MgCl has been photographed at high resolution and analyzed for the rotational structure. Analysis of the low-frequency sub-bands of the 0–0, 0–1, and 0–2 bands showed that there is a nonzero Λ doubling in the common vibrational level ν′ = 0, thereby indicating that the A2Π state is regular and not inverted as presumed by earlier workers. Spin-doubling has been seen in the ν = 1 and 2 levels of the X2Σ+ state. Rotational analysis of the high-frequency sub-band has also been done for the 0–0 band.

Rotational analysis of the 6480 Å absorption of NO2

1979 ◽  
Vol 57 (3) ◽  
pp. 428-441 ◽  
Author(s):  
J. C. D. Brand ◽  
K. J. Cross ◽  
A. R. Hoy
Keyword(s):  
Vibrational Level ◽  
Vibronic Coupling ◽  
Spin Splitting ◽  
Order Effects ◽  
Centrifugal Distortion ◽  
Vibronic Band ◽  
Visible Absorption ◽  
Centrifugal Distortion Constants ◽  
Franck Condon ◽  
Higher Order Effects

About 300 rotational transitions in the 6480 Å region in the visible absorption of NO2 gas have been assigned by laser-excited fluorescence. A majority of the stronger transitions belong to the K = 0 and K = 1 subbands of a vibronic band, T0 = 15 434.9 cm−1, whose upper state is predominantly an a1, vibrational level of the electronic 2B2 basis state. Other groups of relatively weaker lines form (i) a severely-perturbed K = 2 subband attributed to the same series as the K = 0 and 1 subbands; (ii) a well-developed though relatively weak K = 3 subband assigned to a hybrid level of mainly 2A1, character, the transition to this level being induced by vibronic coupling; and (iii) a K = 6 subband assigned to a parent (i.e., 2B2 basis) vibrational level different from that identified at 15 435 cm−1. The spectrum in this region abundantly illustrates the irregularities, 'extra' lines, resonance crossings, and erratic spin splitting now recognized as widespread in the NO2 visible absorption. Rotational constants are not well defined and vary considerably from one subband to another: large pseudo-centrifugal distortion constants are attributed to higher-order effects of the vibronic coupling. Franck–Condon analysis of the intensity distribution in fluorescence leads to a tentative vibrational assignment of 1 60 for the stale at 15 435 cm−1.

Critical assessment: Use of supersonic jet spectrometry for complex mixture analysis (IUPAC Technical Report)

2003 ◽  
Vol 75 (7) ◽  
pp. 975-998 ◽  
Author(s):  
Totaro Imasaka ◽  
D. S. Moore ◽  
T. Vo-Dinh
Keyword(s):  
Electronic State ◽  
Vibrational Level ◽  
Excited Electronic State ◽  
Supersonic Jet ◽  
Complex Mixture ◽  
Chemical Species ◽  
Basic Research ◽  
Analytical Technique ◽  
Detection Techniques ◽  
Supersonic Jet Expansion

When cooled to a temperature of a few K using supersonic jet expansion into a vacuum, a molecule exists in the lowest vibrational level of the ground electronic state and is isolated at collision-free conditions. The absorption or excitation/fluorescence spectrum is then greatly simplified, when transitions occur from this single vibrational level to a limited number of vibrational levels in the excited electronic state. This method, called supersonic jet spectrometry, is a powerful analytical technique because of its high selectivity, since the chemical species can be accurately identified and selectively quantified using the sharp spectral features even for large molecules. Supersonic jet spectrometry has distinct advantages over other low-temperature spectrometries,in that it can be combined with gas-phase separation and detection techniques such as chromatography or mass spectrometry. Therefore, this spectrometric technique can be used as a versatile analytical means, not only for basic research on pure substances, but also for practical trace analysis of chemical species in multicomponent samples (e.g., in biological monitoring or in environmental monitoring).

The D2Σ+ – A2Πi and C2Πr – A2Πi transitions of AlO

1985 ◽  
Vol 63 (9) ◽  
pp. 1162-1172 ◽  
Author(s):  
M. Singh ◽  
M. D. Saksena
Keyword(s):  
High Resolution ◽  
Electronic State ◽  
Rotational Structure ◽  
Rotational Constants ◽  
Vibrational Levels ◽  
Lower Electronic State ◽  
The Common ◽  
First Time

Several bands of the D2Σ+ – A2Πi and C2Πr – A2Πi transitions of AlO have been photographed at high resolution and analyzed for the rotational structure. Rotational structure in the vibrational levels ν = 0, 1, 2, 3, and 4 of the common lower electronic state A2Πi has been investigated for the first time. Rotational perturbations have been observed in the A2Πi state. The equilibrium rotational constants of the A2Πi state are Be = 0.53705 cm−1 and αe = 0.00491 cm−1.

Rotational Structure at the Long Wavelength End of the 2900 Å System of SO2

1974 ◽  
Vol 52 (15) ◽  
pp. 1443-1457 ◽  
Author(s):  
Y. Hamada ◽  
A. J. Merer
Keyword(s):  
Electronic State ◽  
Geometric Structure ◽  
Theoretical Calculations ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
Long Wavelength ◽  
Isotope Data ◽  
Type C

Rotational analyses have been carried out for the three longest wavelength bands observable in the '2900 Å system' of SO2 (at 3340, 3359, and 3395 Å). Although the bands are perturbed quite severely it has been possible to prove that they are type C bands, and that the approximate upper state geometric structure of the molecule is r(S—O) = 1.53 Å, [Formula: see text]. Comparison with the theoretical calculations of Hillier and Saunders now leaves little doubt that the upper electronic state is the π → π* 1A2 state, appearing in absorption by Herzberg–Teller mixing through Q3′(b2), as recently proposed by Dixon and Hallé. A vibrational numbering for these bands is given, which is consistent with the inertial defect obtained from the rotational analysis, and with recent isotope data published by Brand and Nanes: the 3395 Å band appears to be 031–000, and the electronic origin falls near 27 930 cm−1.

Sign in / Sign up

Export Citation Format

Share Document