The lowest valence and Rydberg states in the dipole-allowed absorption spectrum of nitrogen. A survey of their interactions

1969 ◽  
Vol 47 (5) ◽  
pp. 547-561 ◽  
Author(s):  
Kurt Dressler
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Molecular Nitrogen ◽  
Rydberg States ◽  
Electronic States ◽  
Rotational Constants ◽  
Isotope Shifts ◽  
Valence States ◽  
Singlet States ◽  
Potential Curves

The ungerade singlet states of molecular nitrogen observed up to 115 000 cm−1 have traditionally been designated with some 20 letter symbols. It is shown that these levels do not belong to 20 different electronic states but that all of them can be ordered into six vibrational progressions of three valence states: b1Πu (j, b, d, m, p, q), b′ 1Σu+ (b′, g, g′, f, r), d′(1Σu− or 1Δu?), and of three Rydberg states: c1Πu (l, d″), c′ 1Σu+ (p′, r′, k, s′, h, h′), and o1Πu. The new assignments of observed levels to the states b, b′, c, and c′ are identical with those given by Carroll and Collins on the basis of new high-resolution studies of the absorption spectrum. It is shown here, that the irregularities of the vibrational intervals, rotational constants, isotope shifts, and intensity distributions within these progressions can be interpreted quantitatively on the basis of homogeneous interactions between valence and Rydberg states of the same species, especially between the pairs of states b1Πu + c1Πu and b′ 1Σu+ + c′ 1Σu+. Approximate quantitative deperturbations of the vibrational structures of these four electronic states are derived from a new set of deperturbation criteria, and the resultant potential curves, the electron configurations, and the observed predissociations are discussed. The deperturbation results for the b′ and c′ states are tested in more quantitative detail by Lefebvre-Brion in the adjoining paper.

scholarly journals Absorption Spectrum of As2 Further Analysis of the A→X System and Observation of New Electronic States

1974 ◽  
Vol 29 (3) ◽  
pp. 429-435 ◽  
Author(s):  
Abdel Mooti Sibaï ◽  
Pierre Perdigon ◽  
Ari Topouzkhanian
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Energy Range ◽  
Electronic States ◽  
Absorption Bands ◽  
High Resolution Analysis ◽  
Resolution Analysis

Within the study of the interaction between A and B states of As2 molecule, a high resolution analysis of 16 absorption bands with 11 ≦ υ ≦ 17 in the A ← X system has been performed. The following constants are proposed for the A state: T00 = 40145.9 cm-1, ωe = 262.7 cm-1, ωe xe = 0.48 cm-1, Be = 0.0797 cm-1, De ≅ 3 X 10-8 cm-1 , αe = 0.00031 cm-1 , re = 2.374 Å. Three new vibronic levels have been discovered in the 42 400 -44 500 cm-1 energy range, either directly or by the perturbations they induce in A levels

Absorption spectrum of the NO molecule. VIII. The heterogeneous (2Σ–2Π) interactions between excited states

1968 ◽  
Vol 46 (8) ◽  
pp. 987-1003 ◽  
Author(s):  
Ch. Jungen ◽  
E. Miescher
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Excited States ◽  
Rydberg State ◽  
Vacuum Ultraviolet ◽  
Principal Quantum Number ◽  
Rydberg States ◽  
Infrared Emission ◽  
Strong Interactions ◽  
Rydberg Series

Heterogeneous perturbations 2E+ ~ 2Π of largely different magnitudes are observed with high resolution in the vacuum-ultraviolet absorption and in the infrared emission spectrum of the NO molecule. The rotational interactions between 2Σ+ Rydberg states and levels of the B2Π non-Rydberg state are shown to be "configurationally forbidden", but produced by the configuration interaction between the non-Rydberg levels and 2Π Rydberg states. The latter together with the 2Σ+ Rydberg states form p complexes. In this way the interactions display the l uncoupling in the complexes; they can be evaluated theoretically and can be analyzed fully. The cases of the strong interactions D2Σ+(v = 3) ~ B2Π(v = 16)and D2Σ+(v = 5) ~ B2Π(v = 21) and of the weaker D2Σ+(v = 1) ~ B2Π(v = 11), all three observed as perturbations in ε bands crossing 3 bands, are discussed in detail. It is further shown that perturbations between γ bands and β bands as well as perturbations between analogous bands of higher principal quantum number are absent, and thus the assignment of the A2Σ+ and E2Σ+ states to the s Rydberg series is confirmed.

The spectroscopy of H2CS. 1. CS stretch potential curves for singlet states of planar H2CS, obtained by ab initio multireference CI methods

1995 ◽  
Vol 73 (1-2) ◽  
pp. 18-34 ◽  
Author(s):  
M. R. J. Hachey ◽  
F. Grein
Keyword(s):  
Dipole Moments ◽  
Oscillator Strengths ◽  
Excitation Energies ◽  
Valence States ◽  
Singlet States ◽  
Symmetry Species ◽  
Condon Factors ◽  
Combination Modes ◽  
Franck Condon ◽  
Potential Curves

For planar H2CS, (C2ν), the CS stretch potential curves were obtained for the four to six lowest singlet states of each symmetry species by using multireference CI methods. Included were the (n, 4s), (n, 4p), (n, 3d), (π, 4s), and (π, 4p) Rydberg as well as the (n, π*), (π, π*), (σ, π*), (n, σ*), (n0, π*2), and (nπ, π*2) valence states. Vertical and adiabatic excitation energies, equilibrium CS distances, vibrational frequencies for the CS stretching mode, dipole moments, oscillator strengths, and Franck–Condon factors were evaluated and found to be in good agreement with known experimental data. The role of the 1(π, π*) state that diabatically crosses all 1A1 states, including the n2 ground-state configuration, causing many interactions with other states, has been given special attention. The following reassignments and predictions are of interest. (i) A switch of Ẽ and [Formula: see text], with 1A1(n, 4py) corresponding to the Ẽ bands and 1B2(n, 4pz) corresponding to the [Formula: see text] bands is suggested, based on the energetic ordering. (ii) Because of strong Franck–Condon factors, hot bands are suggested to play an important role in the analysis of the CS stretch progression of [Formula: see text]. (iii) The [Formula: see text] system, only studied in low resolution, is predicted to have high intensity and be perturbed due to the crossing of (π, π*) with (n, 4py) in the vertical region. The CS stretch bands should be observable. (iv) Observed combination modes in the [Formula: see text] system may be due to vibronic mixing of (π, π*) with (σ, π*).

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.

The emission spectrum of ReO between 375 and 875 nm: A classification based on rotational analysis and Re16O/Re18O isotope shifts

1984 ◽  
Vol 62 (12) ◽  
pp. 1524-1537 ◽  
Author(s):  
Walter J. Balfour ◽  
Ram. S. Ram
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Electronic States ◽  
Electronic Transitions ◽  
Lower State ◽  
Rotational Analysis ◽  
Isotope Shifts ◽  
Isotopic Shifts

The emission spectrum of the ReO molecule has been photographed under high resolution between 375 and 875 nm. In addition to the 711.9 and 404.5 nm systems previously studied a large number of new electronic transitions have been classified on the basis of Re16O/Re18O isotopic shifts. The rotational structures of 18 bands of Re16O and 1 band of Re18O have been analyzed. Two low-lying electronic states in addition to the known common lower state of the 711.9 and 404.5 nm systems have been identified.

The c3Π – b3Σ+ transition of CO near 8245 cm−1

1987 ◽  
Vol 65 (9) ◽  
pp. 1171-1177 ◽  
Author(s):  
I. Dabrowski ◽  
M. Vervloet ◽  
D.-C. Wang
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Near Infrared ◽  
Electronic States ◽  
Direct Determination ◽  
Fourier Transform Spectroscopy ◽  
Rotational Constants

A transition between two high-lying electronic states of CO, c3Π – b3Σ+, has been observed by high resolution Fourier transform spectroscopy, in the near infrared, around 8245 cm−1. The triplet splittings of both c3Π and b3Σ+ have clearly been observed. The value A = 1.504(12) cm−1 has been determined for c3Π and confirms the previous direct determination of Klopotek and Vidal (J. Opt. Soc. Am. B, 2, 869 (1985)). Because these states were found to be heavily perturbed, only the analysis and effective rotational constants are reported.

scholarly journals High Resolution Spectral Studies of some Diatomic Molecules of Astrophysical Interest

1987 ◽  
Vol 120 ◽  
pp. 91-92 ◽  
Author(s):  
T. K. Balasubramanian ◽  
G. L. Bhale ◽  
Sheila Gopal ◽  
G. Krishnamurthy ◽  
G. Lakshminarayana ◽  
...  
Keyword(s):  
High Resolution ◽  
Diatomic Molecules ◽  
Electronic States ◽  
Spectral Studies ◽  
Laboratory Studies ◽  
Rotational Constants ◽  
Astrophysical Interest

Laboratory studies have been made on molecules of astrophysical interest such as AlO, CO, CrO, SiS, NH+ and OH. Vibrational and rotational constants have been determined more accurately in the various electronic states.

Forbidden absorption bands of O2 in the argon continuum region

1969 ◽  
Vol 47 (17) ◽  
pp. 1805-1811 ◽  
Author(s):  
M. Ogawa ◽  
K. R. Yamawaki
Keyword(s):  
Absorption Spectrum ◽  
Ground State ◽  
Electronic States ◽  
Absorption Bands ◽  
Rotational Constants ◽  
Continuum Region

The absorption spectrum of O2 has been photographed in the argon continuum region with a 3-m vacuum spectrograph at a dispersion of 1.42 Å/mm. Based on the known rotational constants of the ground state, the rotational constants of the upper states have been determined for Tanaka progession (I), β–X3Σg−, progression (II), α1Σu+–X3Σ−, and those of a new band at 1144.6 Å. In a brief discussion of the upper electronic states, it is suggested that both the β state and the upper states of the 1144.6 Å band are 3Σu+ states and their electron configurations are (πg2p)(3pπ) and (πg2p)(4pπ), respectively, and also the α state is (πg2p)(3pπ)1Σu+.

A 4Σ−–2Π TRANSITION OF THE SiF MOLECULE

1962 ◽  
Vol 40 (5) ◽  
pp. 586-597 ◽  
Author(s):  
R. D. Verma
Keyword(s):  
High Resolution ◽  
Ground State ◽  
Electronic States ◽  
Lower State ◽  
Rotational Analysis ◽  
Rotational Constants

The η bands of SiF, in the region 3300–3400 Å, have been photographed in emission at high resolution. A detailed rotational analysis has shown that these bands represent a 4Σ−–2Πτ transition. The lower state is the ground state of the molecule. The principal rotational constants of the upper and lower electronic states in cm−1 are as follows:[Formula: see text]A discussion of the electron configurations is also given.

Spectrum of SO: Analysis of the B3Σ−–X3Σ− and A3 Π–X3Σ− band systems

1969 ◽  
Vol 47 (9) ◽  
pp. 979-994 ◽  
Author(s):  
R. Colin
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Microwave Discharge ◽  
Flash Photolysis ◽  
Band System ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Π State

The absorption spectrum of SO radicals produced by flash photolysis of a mixture of COS + O2 + Ar is investigated. A partial rotational analysis of the previously known bands of the B3Σ−–X3Σ− transition which lie in the region of 1900 to 2400 Å is presented, and the predissociations and perturbations of the B3Σ−state are discussed. A complex red-degraded band system near 2500 Å, previously observed in emission and attributed to SO2, is shown to be due to a 3Π–X3Σ− transition of the SO molecule. Effective rotational constants of the 3Π state are derived from the analysis of these bands photographed at high resolution. In order to obtain the vibrational numbering of the 3Π–X3Σ− bands, these were also photographed in emission from a microwave discharge through a mixture of S18O2 + S16O2. A general discussion of the currently known states of the SO molecule is given.

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