scholarly journals Spectrum of the hydroxyl radical

1969 ◽  
Vol 47 (18) ◽  
pp. 1945-1957 ◽  
Author(s):  
C. Carlone ◽  
F. W. Dalby
Keyword(s):  
High Resolution ◽  
Hydroxyl Radical ◽  
Dissociation Energy ◽  
Spin Splitting ◽  
Oh Radical ◽  
Rotational Constants ◽  
Upper Limit ◽  
Vibrational Levels ◽  
State Formula ◽  
Potential Maximum

The B2Σ+ → A2Σ+ and C2Σ+ → A2Σ+ systems of OH and OD were photographed at high resolution. The apparent dissociation energy D0(A2Σ+) is calculated to be (18 847 ± 15) cm−1 for OH and (19 263 ± 15) cm−1 for OD. An upper limit to D0(X2Π3/2) of OH is deduced to be (35 420 ± 15) cm−1. Evidence for a potential maximum in the B2Σ+ state, which is about 100 cm−1 larger than that in the A2Σ+ state, is presented.The broadening of the rotational lines in several bands of both systems has established a strong predissociation of the A2Σ+ state near ν = 5 in OH. The lifetime of these predissociated levels is ≈10−11 s. A definite identification of the predissociating state has not been possible.Newly-discovered vibrational levels in the C2Σ+ state have led to the following constants, in cm−1, of the OH radical in the C2Σ+ state:[Formula: see text]Rotational constants and spin splitting constants in the A2Σ+ and B2Σ+ states, more accurate than previously available, are presented.

Spectre d'émission du radical P2 : étude de la transition b′3Σu−–X1Σg+

1974 ◽  
Vol 52 (21) ◽  
pp. 2143-2149 ◽  
Author(s):  
J. Brion ◽  
J. Malicet ◽  
H. Guenebaut
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Electronic Transition ◽  
Spin Splitting ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Vibrational Levels

The emission spectrum of the b′3Σu−–X1Σg+ system between 3540–4375 Å and ascribed previously by Mrozowski and Santaram to the a3Σu+–X1Σg+ transition of the P2 molecule, has been photographed under high resolution. The rotational analysis of 7 bands has been carried out and allowed us to determine the rotational constants of the vibrational levels ν′ = 0, 1, and 2 as well as the spin splitting constants λ′ and γ′. The nature of the upper state has been identified as a 3Σu− state, the electronic transition being analogous to the Ogawa–Tanaka–Wilkinson system of N2.

THE LYMAN BANDS OF MOLECULAR HYDROGEN

1959 ◽  
Vol 37 (5) ◽  
pp. 636-659 ◽  
Author(s):  
G. Herzberg ◽  
L. L. Howe
Keyword(s):  
High Resolution ◽  
Vibrational Level ◽  
Ground State ◽  
Molecular Hydrogen ◽  
Equilibrium Constants ◽  
Dissociation Limit ◽  
Vibrational Levels ◽  
State Formula ◽  
Single Formula ◽  
Vibrational Constants

The Lyman bands of H2 have been investigated under high resolution with a view to improving the rotational and vibrational constants of H2 in its ground state. Precise Bv and ΔG values have been obtained for all vibrational levels of the ground state. One or two of the highest rotational levels of the last vibrational level (v = 14) lie above the dissociation limit. Both the [Formula: see text] and ΔG″ curves have a point of inflection at about v″ = 3. This makes it difficult to represent the whole course of each of these curves by a single formula and therefore makes the resulting equilibrium constants somewhat uncertain. This uncertainty is not very great for the rotational constants for which we find[Formula: see text]but is considerable for the vibrational constants ωe and ωexe for which three-, four-, five-, and six-term formulae give results diverging by ± 1 cm−1. The rotational and vibrational constants for the upper state [Formula: see text] of the Lyman bands are also determined. An appreciable correction to the position of the upper state is found.

Vibration bands and molecular rotational constants of nitrous oxide

1953 ◽  
Vol 220 (1143) ◽  
pp. 435-445 ◽  
Keyword(s):  
Nitrous Oxide ◽  
Fine Structure ◽  
High Resolution ◽  
Microwave Spectrum ◽  
Rotational Constants ◽  
Vibrational Levels ◽  
Resonance Interactions ◽  
Vibration Rotation ◽  
Different Levels

Seven vibration-rotation bands of nitrous oxide have been measured with high resolution. The rotational fine structure of each has been analyzed and rotational constants have been derived. The value for B 000 found from four bands is 0·4190 1 cm -1 , agreeing very closely with that determined from the microwave spectrum. Values for the coefficients α i for the different vibrational levels have been determined, and the occurrence of inconsistencies in the calculated values of B v 1 v 2 v 3 for higher vibrational levels confirms previous suggestions that resonance interactions may exist between different levels. Such interactions appear also to disturb the positions of the band origins.

The B′2Σ+ → X2Σ+ systems of MgH and MgD

1976 ◽  
Vol 54 (18) ◽  
pp. 1898-1904 ◽  
Author(s):  
Walter J. Balfour ◽  
Hugh M. Cartwright
Keyword(s):  
High Resolution ◽  
Potential Energy ◽  
Dissociation Energy ◽  
Potential Energy Curve ◽  
Energy Levels ◽  
Rotational Energy ◽  
Energy Curve ◽  
Molecular Constants ◽  
Vibrational Levels

The B′2Σ+ → X2Σ+ systems in MgH and MgD have been studied in emission at high resolution. Vibrational and rotational analyses, which have been performed for 37 bands of MgH and 16 bands of MgD, provide data on the following vibrational levels of the B′ state: MgH, ν = 0–9; MgD, ν = 0–2, 4–6. The following molecular constants (in cm−1) have been determined for the B′ state: MgH, Tc = 22 410, ωc = 828.4, ωcxc = 11.8, Bc = 2.585, Dc = 1.2 × 10−4; MgD, Tc = 22 415, ωc = 598.1, ωcxc = 6.4, Bc = 1.346, Dc = 2.6 × 10−5. The dissociation energy, Dc, in the B′ state is estimated to be 10 900 cm−1 (MgH), 11 200 cm−1 (MgD). The RKR potential energy curve for the B′ state has been calculated. A correlation of the rotational perturbations in the B′ → X system with the positions of rotational energy levels in the A2Π and B′2Σ+ states has been made. Observations for the low-lying states of MgH are compared with similar available data for related hydrides.

Vibration-rotation bands of monodeuteroacetylene and the molecular dimensions

1956 ◽  
Vol 234 (1198) ◽  
pp. 306-317 ◽  
Keyword(s):  
High Resolution ◽  
Ground State ◽  
Fermi Resonance ◽  
Rotational Constants ◽  
Bond Lengths ◽  
Vibrational Levels ◽  
Vibration Rotation ◽  
Molecular Dimensions

Some vibration-rotation bands of monodeuteroacetylene have been measured with high resolution. Values have been derived for the coefficients α i relating the rotational constants in different vibrational levels, as follows: α 2 = + 0⋅00439, α 3 = + 0⋅00638, α 4 = — 0⋅0032 2 , α 5 = — 0⋅0011. Using the value B 00000 = 0⋅9910 5 cm -1 , also determined from many bands, a new value, B e = 0⋅9948, has been obtained leading to new estimates for the bond lengths r e CH = 1⋅058 Å, and r e C≡C = 1⋅205 0 . The l -doubling coefficient has been determined in two states, namely, q 00010 = 0⋅0056 and q 00003 = 0⋅0072. In the ground state the results are in accordance with a centrifugal stretching coefficient D = 0⋅7 x 10 -6 , but in some higher levels a markedly different value is derived, which may, however, arise through the effects of Fermi resonance.

THE EMISSION SPECTRUM OF THE PH+ MOLECULE

1957 ◽  
Vol 35 (8) ◽  
pp. 901-911 ◽  
Author(s):  
N. A. Narasimham
Keyword(s):  
Emission Spectrum ◽  
Dissociation Energy ◽  
Hollow Cathode ◽  
Hollow Cathode Discharge ◽  
Spin Splitting ◽  
Rotational Constants ◽  
Π State ◽  
Large Spin

A system of three red degraded bands at 3854, 4228, and 3567 Å has been obtained in emission from a hollow cathode discharge through helium containing a little phosphorus vapor and hydrogen. Rotational analyses of the bands show that they are the 0–0, 0–1, and 1–0 bands of a 2Δ—2Π transition of the PH+ molecule. The 2Δ state is regular with small spin splitting (case b) while the 2Π state is regular with large spin splitting (case a). For ν = 0, the F1 levels of the 2Δ state with [Formula: see text] and the F2 levels with [Formula: see text] are predissociated. Also the lines arising from the F1 levels of the 2Δ state with ν = 1 are found to be extremely weak compared to those arising from the F2 levels. Vibrational and rotational constants have been determined and the dissociation energy has been found to be 3.06 ± 0.25 ev.

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.

The structure of the Goldstein-Kaplan bands of N 2

1963 ◽  
Vol 272 (1349) ◽  
pp. 270-283 ◽  
Keyword(s):  
High Resolution ◽  
Molecular Orbital ◽  
Dissociation Energy ◽  
Ultra Violet ◽  
Vibrational Structure ◽  
The State ◽  
Spin Interaction ◽  
Single System ◽  
Unusual Structure ◽  
Rotational Constants

Three bands of the Goldstein-Kaplan system of N 2 have been photographed under high resolution and rotational analyses made. It is shown conclusively that the blue-green Goldstein bands and the ultra-violet Kaplan bands form a single system having the well-known B 3 Π g state as the lower level. The upper state, C' , is identified as 3 Π u with the rotational constants B 0 = 1·0496 cm -1 , D 0 = 10·9 x 10 -6 cm -1 , H 0 = 8·3 x 10 -10 cm -1 . The state shows case b coupling and has an unusual structure in which spin-spin interaction appears to play an important part. To account for the unusual properties of the state it is suggested that it arises from a mixture of two or more molecular orbital configurations. The vibrational structure indicates either that predissociation occurs or that the state has a small dissociation energy. The interaction of the C ´ and C states is discussed and is suggested to be responsible for the observed irregularities in the C 3 Π u state.

The Electronic Spectrum of HF. I. The B1Σ+–X1Σ+ Band System

1973 ◽  
Vol 51 (4) ◽  
pp. 434-445 ◽  
Author(s):  
G. Di Lonardo ◽  
A. E. Douglas
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Emission Spectrum ◽  
Electronic Spectrum ◽  
Dissociation Energy ◽  
Band System ◽  
Vibrational Levels ◽  
Internuclear Distances ◽  
X State ◽  
Potential Curves

The electronic emission and absorption spectrum of HF has been photographed at high resolution with a 10 m grating spectrograph. The emission, which extends from 2670 to 1480 Å, consists entirely of bands of the B1Σ+–X1Σ+ (previously denoted as the V1Σ+–X1Σ+)system. From the analysis of 51 bands of the emission spectrum, constants of the vibrational levels of the X state from ν = 7 and 19 and of the B state from ν = 0 to 10 have been determined. The dissociation energy of HF has been found to be D0(HF) = 47 333 ± 60 cm−1. In the absorption spectrum, 56 bands of the B–X system have been identified. Vibrational levels of the B state between ν = 14 and 26 were found to be well behaved and readily analyzed, but levels between ν = 26 and 73 were found to be highly perturbed. Rydberg–Klein–Rees potential curves have been calculated for the B and X states and it is shown that at large internuclear distances the bonding of the B state is almost entirely ionic.

THE SPECTRUM OF SiH AND SiD

1965 ◽  
Vol 43 (12) ◽  
pp. 2136-2141 ◽  
Author(s):  
R. D. Verma
Keyword(s):  
Dissociation Energy ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Upper Limit ◽  
New States

Two new systems of SiH and SiD in the regions around 3 250 Å and 2 050 Å in addition to the well-known 2Δ−2Π system have been recorded in absorption and their rotational analysis (except for the 2Δ−2Π system of SiH) has been carried out. The new states are 2Σ+ at T0 = 30 974.69 cm−1 and 2Δ at T0 = 48 603.46 cm−1. The rotational constants for all the states known in SiD have been determined. The upper limit of the dissociation energy of SiH has been fixed at 24 680 cm−1 by predissociation.

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