THE ABSORPTION SPECTRA OF HNO AND DNO

1962 ◽  
Vol 40 (3) ◽  
pp. 322-347 ◽  
Author(s):  
J. L. Bancroft ◽  
J. M. Hollas ◽  
D. A. Ramsay
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Absorption Spectra ◽  
Line Width ◽  
Geometrical Parameters ◽  
Rotational Constants ◽  
Long Wavelength ◽  
A Value ◽  
Emission Studies

The long wavelength 1A″ – 1A′ transition of HNO and DNO has been studied in absorption under high resolution using much greater absorption intensities than in the earlier work of Dalby. Seven new bands of HNO and six new bands of DNO have been found and analyzed. Values for [Formula: see text] have been found and are: [Formula: see text] and [Formula: see text]. Equilibrium rotational constants [Formula: see text], [Formula: see text], and [Formula: see text] have been determined for both molecules. The values for HNO give zero inertial defect but the values for DNO are less satisfactory, presumably due to resonance between pairs of levels (1, [Formula: see text], [Formula: see text]) and (0, [Formula: see text], [Formula: see text]). Equilibrium values for the geometrical parameters of the excited state have been evaluated and are: [Formula: see text] [Formula: see text], [Formula: see text].Some of the rotational lines of the (101)–(000) band of HNO are found to be slightly diffuse, the maximum observed line width being ~0.7 cm−1. This observation confirms the predissociation limit found in the emission studies of Clement and Ramsay and gives a value for the lifetime of the molecule in the excited state, viz τ ~7.6 × 10−12 sec. The predissociation is weak and the possible states causing this predissociation are discussed.

Nonparametric High-Resolution Coherent 3D Spectroscopy as a Simple and Rapid Method for Obtaining Excited-State Rotational Constants

2018 ◽  
Vol 122 (44) ◽  
pp. 8794-8801
Author(s):  
Thresa A. Wells ◽  
Victoria J. Barber ◽  
Muhire H. Kwizera ◽  
Patience Mukashyaka ◽  
Peter C. Chen
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Rapid Method ◽  
Rotational Constants

Investigation of the Structure of the ν1 Band of Monochloroacetylene

1968 ◽  
Vol 23 (12) ◽  
pp. 2098-2099 ◽  
Author(s):  
Rauno Anttila ◽  
Mikko Huhanantti
Keyword(s):  
Excited State ◽  
Rotational Structure ◽  
Rotational Constants ◽  
A Value ◽  
Type Band

The ν1 band of monochloroacetylene was investigated. The rotational structure of this Σ-Σ type band was resolved and lines of both HCCCl35 and HCCCl37 were assigned. The rotational constants of these molecules were obtained both in the ground and the excited state. For the D constant of HCCCl35 a value of (4.8 ±1) × 10-8 cm-1 was obtained from the band. The constant was also computed theoretically and the result was 4.6 × 10-8 cm-1.

X-RAY ABSORPTION SPECTRA OF SOME SMALL POLYATOMIC MOLECULES

2002 ◽  
Vol 09 (01) ◽  
pp. 159-164 ◽  
Author(s):  
K. C. PRINCE ◽  
R. RICHTER ◽  
M. DE SIMONE ◽  
M. CORENO
Keyword(s):  
Fine Structure ◽  
Excited State ◽  
High Resolution ◽  
Formic Acid ◽  
Absorption Spectra ◽  
Organic Molecules ◽  
Polyatomic Molecules ◽  
X Ray ◽  
Vibrational Progression ◽  
X Ray Absorption

We report the Near Edge X-ray Absorption Fine Structure Spectra (NEXAFS) of a series of oxygen-containing organic molecules, namely formaldehyde, acetaldehyde, acetone, formic acid, methanol and dimethyl ether (DME), measured with high resolution at the carbon and oxygen edges. A vibrational progression has been observed at the oxygen 1s → π* resonance of formaldehyde, indicating that this state is bound with an excited state C=O stretching frequency of 136 meV. The spectra are compared with previous measurements and the applicability of the chromophore concept is tested for the functional groups present in these molecules.

ULTRAVIOLET ABSORPTION SPECTRA OF HCN AND DCN: I. THE α—X AND β—X SYSTEMS

1957 ◽  
Vol 35 (8) ◽  
pp. 842-879 ◽  
Author(s):  
G. Herzberg ◽  
K. K. Innes
Keyword(s):  
Fine Structure ◽  
Absorption Spectra ◽  
Excited States ◽  
Linear Structure ◽  
Ultraviolet Absorption ◽  
Geometrical Parameters ◽  
Rotational Analysis ◽  
Long Wavelength ◽  
Non Linear ◽  
The Asymmetry

The ultraviolet absorption spectra of HCN and DCN have been investigated below 2000 Å. Four band systems have been found of which two, α—X and β—X, are described and analyzed in the present paper. At the long wavelength end the α—X system in both HCN and DCN consists of simple progressions of sharp bands whose fine structure has been measured. At shorter wavelengths diffuseness (predissociation) sets in gradually but at somewhat different energies in HCN and DCN. Both the vibrational and rotational analyses lead independently and unambiguously to the conclusion that in the upper state, α, unlike in the ground state, the molecule is non-linear. The geometrical parameters obtained from the rotational fine structure are r0(CH) = 1.140 Å, r0(CN) = 1.297 Å, and [Formula: see text]H—C—N = 125.0°. Two vibrational frequencies in the α state are established: for HCN, ν1 = 1506, ν2 = 949; for DCN, ν1 = 1506, ν2 = 735 cm−1. The CH stretching frequency has not been found.The β—X system has been clearly observed only for DCN. In HCN it is apparently so strongly predissociated that its presence among the diffuse α—X bands is difficult to establish. In the β state, as in the α state, the molecule is bent. The somewhat fragmentary rotational analysis leads to r0(CN) = 1.334 Å and [Formula: see text]D—C—N = 114.5° when r0(CD) = 1.140 Å is assumed. Only one vibrational frequency, ν2 = 731 cm−1, has been established in the β state of DCN. The vibrational quantum number v2 is uncertain since no isotope effect is available to establish the position of the 0–0 band.In the rotational analysis, particularly of the α—X system, the effects of the asymmetry of the molecule in the upper state are clearly demonstrated by the doubling of the levels with K = 1 and K = 2 and the large contributions of the asymmetry to the terms in J2(J + 1)2. From the sign of the K-type doubling for K = 1 it follows unambiguously that both the α and the β state belong to the species A″, i.e. the electronic eigenfunctions are antisymmetric with respect to the plane of the molecule. It appears probable that both transitions α—X and β—X correspond to forbidden transitions (1Δ—1Σ+ and 1Σ−—1Σ+) of the linear case. The non-linear structure of the excited states is briefly discussed in terms of electron configurations.A number of interesting features of the predissociation in the α state are pointed out. It is shown that the dissociation products are in all probability H + CN(2Π).

HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: IV. ROTATIONAL RAMAN SPECTRUM OF CYANOGEN

1954 ◽  
Vol 32 (10) ◽  
pp. 635-638 ◽  
Author(s):  
C. K. Møller ◽  
B. P. Stoicheff
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectrum ◽  
High Resolution ◽  
Bond Length ◽  
Second Order ◽  
Single Bond ◽  
Rotational Constants ◽  
A Value ◽  
Symmetric Molecule ◽  
Concave Grating

The rotational Raman spectrum of cyanogen gas at [Formula: see text] atm. pressure has been photographed in the second order of a 21 ft. concave grating spectrograph. The simplicity of the spectrum and the observed intensity alternation of the lines show that C2N2 is a linear symmetric molecule. An analysis of the spectrum yields for the rotational constants[Formula: see text]By assuming a value for the C≡N bond length of 1.157 Å, the length of the C—C single bond was calculated to be 1.380 Å.

High-resolution study of the υ9 fundamental band of trans-glyoxal

2001 ◽  
Vol 79 (2-3) ◽  
pp. 479-482 ◽  
Author(s):  
D B Braund ◽  
A RH Cole
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Ground State ◽  
Type B ◽  
Rotational Constants ◽  
Fundamental Band ◽  
Stretching Vibration ◽  
Resolution Study

The spectrum of trans-glyoxal has been recorded at a resolution of about 0.004 cm–1 in the region from 2770 to 2900 cm–1. 1549 lines have been assigned to the type B band due to the υ9 (bu) fundamental (antisymmetric C–H stretching vibration). The ground-state rotational constants confirm earlier values and new constants are determined for the excited state of υ9. PACS No.: 33.20E

A new predissociated 2Σ+ state of the BeCl molecule

1977 ◽  
Vol 55 (6) ◽  
pp. 582-588 ◽  
Author(s):  
M. Carleer ◽  
B. Burtin ◽  
R. Colin
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Dissociation Energy ◽  
Intensity Distribution ◽  
Internuclear Distance ◽  
Ground State ◽  
Thermochemical Data ◽  
Molecular Constants ◽  
Equilibrium Internuclear Distance ◽  
A Value

Ten bands belonging to a new B2Σ+–X2Σ+ system of the BeCl molecule have been discovered in emission between 1990 and 2175 Å. The bands of both isotopes Be35Cl and Be37Cl have been photographed at high resolution and the most intense ones have been rotationally analyzed. Only three levels of the excited state have been observed and they present vibrational and rotational perturbations. The principal molecular constants of the new B2Σ+ state of Be35Cl are: v00 = 48 827.6, ΔG1/2 = 925.5, ΔG3/2 = 1212.7, Be = 0.7751, De = 3.5 × 10−6 cm−1, and the equilibrium internuclear distance is 1.7422 Å. The unusual intensity distribution in the bands can be tentatively interpreted as the result of an inverse predissociation which leads to a value of D″0 = 27 800 ± 500 cm−1 (3.45 ± 0.06 eV) for the dissociation energy of the ground state of the BeCl molecule. This value is at variance with thermochemical data.

HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: V. ROTATIONAL SPECTRA OF ALLENE, ALLENE-d4, AND ALLENE-1,1-d2

1955 ◽  
Vol 33 (12) ◽  
pp. 811-818 ◽  
Author(s):  
B. P. Stoicheff
Keyword(s):  
Raman Spectroscopy ◽  
Double Bond ◽  
High Resolution ◽  
Raman Spectra ◽  
Second Order ◽  
Rotational Constants ◽  
Rotational Spectra ◽  
A Value ◽  
Carbon Double Bond

The pure rotational Raman spectra of allene, allene-d4 and allene-1,1-d2 were photographed in the second order of a 21 ft. grating. Two plates of each spectrum were analyzed yielding the following values for the rotational constants:[Formula: see text]These constants lead to the value r0(C=C) = 1.3088 ± 0.001 Å. Also if a value of r0(C—H) = 1.07 ± 0.01 Å is assumed, then [Formula: see text]. It is noted that the length of the carbon–carbon double bond in allene is significantly shorter than that in ethylene.

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.

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