16O3 Rotational and Centrifugal Distortion Constants of the Ground State from A- and S-Reduced Hamiltonians

2019 ◽  
pp. 21-22
Author(s):  
Guy Guelachvili ◽  
Nathalie Picqué
Keyword(s):  
Ground State ◽  
Centrifugal Distortion ◽  
Centrifugal Distortion Constants

Preferred Rotameric Conformations of Isobutyraldehyde, Their Dipole Moments and Vibrationally Excited States by Microwave Spectroscopy

1986 ◽  
Vol 41 (3) ◽  
pp. 483-490 ◽  
Author(s):  
O. L. Stiefvater
Keyword(s):  
Oxygen Atom ◽  
Excited States ◽  
Ground State ◽  
Dipole Moments ◽  
Microwave Spectroscopy ◽  
Centrifugal Distortion ◽  
Gauche Conformation ◽  
Vibrationally Excited ◽  
Trans Conformation ◽  
Centrifugal Distortion Constants

The earlier prediction of the preferred and the less stable rotameric conformations of isobutyraldehyde, (CH3)2CHCHO, has been confirmed experimentally by microwave spectroscopy. The compound exists mainly in a gauche conformation, in which one of the methyl groups is eclipsed by the oxygen atom, and the less stable rotamer is the trans conformation, in which the oxygen atom eclipses the isopropyl hydrogen.Ground state rotational constants (in MHz) and centrifugal distortion constants (in kHz), together with dipole moments (in D), are:Rotation spectra due to three torsionally excited states of each rotamer have been identified, along with satellites arising from CH3 internal rotation and CC2 wagging.

scholarly journals Tunable Diode Laser Spectra and Assignment of the 748 cm-1 Band of Propane

1989 ◽  
Vol 44 (4) ◽  
pp. 316-324 ◽  
Author(s):  
G. Gassler ◽  
B. Reißenauer ◽  
W. Hüttner
Keyword(s):  
Fourier Transform ◽  
Diode Laser ◽  
Ground State ◽  
Quantum States ◽  
Rotational Structure ◽  
Tunable Diode Laser ◽  
Ftir Spectrum ◽  
Centrifugal Distortion ◽  
Low Resolution ◽  
Centrifugal Distortion Constants

Abstract The rotational structure of the 748 cm-1 c-type CH2-rocking fundamental of propane was analysed using tunable diode laser (TDL) techniques. On grounds of a low-resolution Fourier transform (FTIR) spectrum and of the known ground-state rotational and centrifugal-distortion constants, some 700 transitions were measured and assigned in several regions of the band. The upper-state constants determined in this way allow the prediction of rovibrational frequencies to within 0.003 cm-1, covering quantum states up to J = 50 and Ka = 20. The band appears unperturbed.

High Resolution Infrared Detection of O=PF in the Gas Phase

1999 ◽  
Vol 54 (8-9) ◽  
pp. 507-512 ◽  
Author(s):  
P. Paplewski ◽  
H. Bürger ◽  
H. Beckers
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Gas Phase ◽  
Ground State ◽  
Infrared Detection ◽  
Centrifugal Distortion ◽  
Perfect Agreement ◽  
The Matrix ◽  
Centrifugal Distortion Constants ◽  
Matrix Ir Spectra

Short-lived phosphenous fluoride, 0=PF, has been made by flash pyrolysis of F2POPF2 in Ar at 1200°C and detected by gas phase IR spectroscopy. The υ1 band, υ0 = 1297.5372 cm-1 , has been studied with a resolution of 8 x 10-3 cm-1 , and about 1500 transitions have been assigned. These were fitted using a Watson-type Hamiltonian, σ = 1.5 x 10-3 cm-1 , to excited state parameters up to quartic centrifugal distortion constants. The υ2 band was located at 819.58 cm-1 . An extended set of ground state parameters was obtained by combining recently measured microwave transitions with ground state combination differences formed from υ1 transitions. The experimental results are in perfect agreement with the matrix IR spectra, mw measurements and ab initio calculations but disagree with a recently claimed low resolution detection of OPF in the gas phase.

Theoretical calculation of the low-lying electronic states of the LaH molecule

2014 ◽  
Vol 92 (9) ◽  
pp. 855-861 ◽  
Author(s):  
Salman Mahmoud ◽  
Mahmoud Korek
Keyword(s):  
Potential Energy ◽  
Internuclear Distance ◽  
Ground State ◽  
Electronic States ◽  
Electronic Energy ◽  
Centrifugal Distortion ◽  
Harmonic Frequency ◽  
Rotational Constants ◽  
Centrifugal Distortion Constants ◽  
First Time

The potential energy curves of the low-lying electronic states of the LaH molecule are reported via the CASSCF method with multireference calculations (single and double excitations with Davidson corrections). Twenty-four low-lying electronic states of the LaH molecule in the representation 2s+1Λ(+/−) below 20 000 cm−1 were investigated along with five lower electronic states in the Ω representation. The harmonic frequency ωe, the equilibrium internuclear distance Re, the rotational constants Be, and the electronic energy with respect to the ground state Te were calculated for these states. Twelve new electronic states are investigated in the present work for the first time that have not yet been observed experimentally. Using the canonical functions approach, the eigenvalues Ev, the rotational constants Bv, the centrifugal distortion constants Dv, and the abscissas of the turning points Rmin and Rmax were calculated for the investigated electronic states up to vibrational level v = 43.

The ν5 Fundamental Bands of N2H2 and N2D2

1974 ◽  
Vol 52 (4) ◽  
pp. 340-344 ◽  
Author(s):  
M. Carlotti ◽  
J. W. C. Johns ◽  
A. Trombetti
Keyword(s):  
Absorption Spectrum ◽  
Infrared Absorption ◽  
Ground State ◽  
Infrared Absorption Spectrum ◽  
Geometrical Parameters ◽  
Centrifugal Distortion ◽  
Trans Conformation ◽  
Complete Set ◽  
Centrifugal Distortion Constants ◽  
First Time

The infrared absorption spectrum of diimide (N2H2) in the 3.2 μm region has been reexamined at higher resolution than previously, and that of dideuterodiimide (N2D2) at 4.3 μm has been recorded for the first time. The ν5 fundamental (A- and B-type hybrid band) for both isotopic molecules has been analyzed, and a complete set of rotational and centrifugal distortion constants for the ground and ν5 = 1 states have been determined. The rotational constants of the ground states are (cm−1) [Formula: see text] and the following geometrical parameters were obtained for the planar trans-conformation of diimide : [Formula: see text] From the intensity alternation observed in the J structure of N2H2 spectrum, it is concluded that diimide has a totally symmetric ground state.

Study of the C-D Stretching Vibration Bands v1 of DCCF and DCCBr

1974 ◽  
Vol 29 (5) ◽  
pp. 698-701 ◽  
Author(s):  
Mikko Huhanantti
Keyword(s):  
Ground State ◽  
Force Constants ◽  
Centrifugal Distortion ◽  
Vibrational States ◽  
Rotational Constants ◽  
Stretching Vibration ◽  
Geometrical Data ◽  
Experimental Values ◽  
Centrifugal Distortion Constants

Abstract The rotational structures of the ν1 bands of the deuterated monohaloacetylenes DCCF and DCCBr were investigated. The rotational constants B in the ground state and in the vibrational states involved were obtained. The centrifugal distortion constants D were calculated from the force constants and the geometrical data, too. The results D = 8.7 x 10-8 cm-1 for DCCF and D = 1.9 x 10-8 cm-1 for DCCBr are compatible with the experimental values (12 ± 4) x 10-8 cm-1 and(2±2) x 10-8 cm-1, respectively.

Ground State Centrifugal Distortion Constants of Trans-Acrolein, CH2 = CH — CHO from the Microwave and Millimeter Wave Rotational Spectra 1,2

1975 ◽  
Vol 30 (8) ◽  
pp. 1001-1014 ◽  
Author(s):  
Manfred Winnewisser ◽  
Gisbert Winnewisser ◽  
T. Honda ◽  
E. Hirota
Keyword(s):  
Ground State ◽  
Vibrational State ◽  
Line Search ◽  
Frequency Region ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Rotational Spectra ◽  
Measured Absorption ◽  
Centrifugal Distortion Constants ◽  
Line Positions

Abstract The pure rotational spectrum of trans-acrolein in the ground vibrational state has been assigned in the frequency region from 8 GHz to 180 GHz. The measured absorption lines encompass a-type transitions from the qRK, qQ1, qQ2 branches and 6-type transitions from the rP0, rP1, rP2, rR0 brandies for values of J up to 23. The rotational constants have been refined and all quartic and sextic centrifugal distortion constants have been determined using Watson's reduced Hamiltonian. This information has been used to predict line positions of astrophysical interest to warrant the interstellar line search for trans-acrolein.

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