Spectre d'émission de la molécule PO : transitions D2Π–B2Σ+ et D′2Π–B2Σ+ des molécules P16O et P18O. Reconsidération de l'état de valence D′2Π

1974 ◽  
Vol 52 (2) ◽  
pp. 177-186 ◽  
Author(s):  
B. Coquart ◽  
M. Da Paz ◽  
J. C. Prudhomme
Keyword(s):  
Vibrational Levels ◽  
Π State

New vibrational levels of the D′2Π state for P16O and P18O interacting with the level ν = 0 of the D2Π state are studied by means of a transition to the B2Σ+ state. Deperturbation calculations have been carried out. The results obtained lead us to look at two hypotheses. In particular, the eventuality is considered that D′2Π and B′2Π are the same state, some high levels of which are observed here.

BAND SPECTRUM AND STRUCTURE OF THE CH+ MOLECULE; IDENTIFICATION OF THREE INTERSTELLAR LINES

1942 ◽  
Vol 20a (6) ◽  
pp. 71-82 ◽  
Author(s):  
A. E. Douglas ◽  
G. Herzberg
Keyword(s):  
Ground State ◽  
Band System ◽  
Lower State ◽  
Band Spectrum ◽  
Interstellar Space ◽  
Molecular Constants ◽  
Vibrational Levels ◽  
State Formula ◽  
Heat Of Dissociation ◽  
Π State

In a discharge through helium, to which a small trace of benzene vapour is added, a new band system of the type 1Π – 1Σ is found which is shown to be due to the CH+ molecule. The R(0) lines of the 0–0, 1–0, and 2–0 bands of the new system agree exactly with the hitherto unidentified interstellar lines 4232.58, 3957.72, 3745.33 Å, thus proving that CH+ is present in interstellar space. At the same time this observation of the band system in absorption shows that the lower state 1Σ is the ground state of the CH+ molecule. The new bands are closely analogous to the 1II – 1Σ+ BH bands. The analysis of the bands leads to the following vibrational and rotational constants of CH+ in its ground state: [Formula: see text], Be″ = 14.1767, αe″ = 0.4898 cm.−1. The internuclear distance is re″ = 1.1310∙10−8 cm. (for further molecular constants see Table V). From the vibrational levels of the upper 1Π state the heat of dissociation of CH+ can be obtained within fairly narrow limits: D0(CH+) = 3.61 ± 0.22 e.v. From this value the ionization potential of CH is derived to be I(CH) = 11.13 ± 0.22 e.v. The bearing of this value on recent work on ionization and dissociation of polyatomic molecules by electron impacts is briefly discussed.

Emission Spectrum of the PO Molecule. Part III. Spectrum in the Red Region

1972 ◽  
Vol 50 (13) ◽  
pp. 1579-1586 ◽  
Author(s):  
S. Guha ◽  
S. S. Jois ◽  
R. D. Verma
Keyword(s):  
Emission Spectrum ◽  
Structure Study ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
Vibrational Levels ◽  
Π State

Four new bands in the red region are observed which have been described in terms of A2Σ+–B2Σ+ and F2Σ+–B2Σ+ systems. A rotational analysis together with deperturbation calculation of one band at 6763 Å has shown that A2Σ+ (ν = 7) and F2Σ+ (ν = 0) vibrational levels are involved in a homogeneous perturbation. The rotational structure study of three bands of a new transition I2Σ+–A2Σ+ has been carried out. From the study of heterogeneous perturbations observed in the I vibrational levels, it has been suggested that the perturbing state is a 2Π state arising from the 3d complex.

Further results relating to the electronic spectrum of 175Lu16O

1986 ◽  
Vol 64 (3) ◽  
pp. 246-251 ◽  
Author(s):  
A. Bernard ◽  
C. Effantin
Keyword(s):  
Least Squares ◽  
Electronic Spectrum ◽  
Ground State ◽  
Rotational Analysis ◽  
Least Squares Fitting ◽  
Fitting Procedure ◽  
Vibrational Levels ◽  
Unique Band ◽  
Π State ◽  
New System

Further results are presented concerning the three known systems of the molecule LuO; i.e., A2Π, B2Π, C2Σ+ → X2Σ+. The observed wavenumbers in each of the 12 analyzed bands are reduced using an iterative, least squares fitting procedure. Rotational constants are given for vibrational levels ν = 0 and 1 in the C state and up to ν = 7 in the X and B states. The 1–1 band of the A → X system is partly analyzed. These new calculations confirm level B to be the 3/2 component of a 2Π state; but they give no such confirmation for the identification of the A level, whose 2Π nature is well established, as the 1/2 component of the same state.Moreover, a unique band at 5120 Å that cannot be classified into any of the three known systems is described and attributed to a new system of LuO. A partial rotational analysis is made showing that the band corresponds to a transition involving the level ν = 0 in the ground state. The nature of the upper state is discussed.

New results on the D2Π and B′2Π states of the PO molecule

1976 ◽  
Vol 54 (6) ◽  
pp. 695-708 ◽  
Author(s):  
S. Ghosh ◽  
S. Nagaraj ◽  
R. D. Verma
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Vibrational Level ◽  
Rotational Analysis ◽  
X Band ◽  
Vibrational Levels ◽  
Π State

A rotational analysis of the D–X and D′–X band systems of PO in the region 1900–2100 Å has been reinvestigated from an absorption spectrum taken at high resolution. A new ν = 1 vibrational level of the D2Π state of PO interacting with a new vibrational level of the D′2Π state has been studied in detail. Two other new vibrational levels, ν = 2 and 3, of D2Π have been recorded and studied in detail. A rigorous deperturbation of the D and D′ levels has been carried out. It has been shown that D′2Π and B′2Π are one and the same state of the PO molecule. A new band overlapped by the D′–X, 26–0 band has been attributed to the B2Σ+–X2Π transition.

Spectrum of the CN molecule. I. Absorption in the vacuum ultraviolet

1970 ◽  
Vol 48 (10) ◽  
pp. 1192-1199 ◽  
Author(s):  
Barry L. Lutz
Keyword(s):  
Vacuum Ultraviolet ◽  
Band System ◽  
Vibrational Analysis ◽  
Electronic States ◽  
Ultraviolet Absorption Spectrum ◽  
Molecular Constants ◽  
Weak Band ◽  
Vibrational Levels ◽  
First Time ◽  
Π State

The vacuum ultraviolet absorption spectrum of CN is observed for the first time revealing a weak band system between 1490 and 1820 Å. Rotational and vibrational analysis shows the upper state to be the known E2Σ+ state. Four new vibrational levels are reported, resulting in the following molecular constants for the E state (cm−1):[Formula: see text]The strength of the absorption and its significance in astrophysics is discussed. The dissociation limits and the electron configurations of all known electronic states of CN are also discussed, and a tentative assignment of a previously unassigned 2Π state is proposed.

ABSORPTION SPECTRUM OF THE NO MOLECULE: VI. BAND STRUCTURES BELOW 1 600 Å, RYDBERG STATES C2Π, D2Σ+, K2Π, M2Σ+, S2Σ+, NON-RYDBERG STATES B2Π, L2Π AND THEIR INTERACTIONS

1966 ◽  
Vol 44 (7) ◽  
pp. 1525-1539 ◽  
Author(s):  
A. Lagerqvist ◽  
E. Miescher
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Fourth Order ◽  
Rydberg States ◽  
Liquid Oxygen ◽  
Interaction Energies ◽  
Band Structures ◽  
Vibrational Levels ◽  
Π State ◽  
Potential Curves

The study of the absorption spectrum of the NO molecule has been continued on plates taken in the fourth order of a 10.5-m vacuum spectrograph. The spectra of 14N16O, 15N16O, 14N18O, and 15N18O gases, each kept at liquid-oxygen temperature, were photographed separately. Rotational analyses were carried out for many bands observed below 1 600 Å. Constants for levels of the Rydberg complexes 3p, 4s, 4p, and 5s have been derived. These levels include ν = 5 and ν = 6 of the C2Π state, levels that interact with the levels ν = 21 and 24 respectively of the configurationally different B2Π state. It is shown that the vibrational levels, now well established above the energy where the potential curves of the C and B states cross, are to be attributed to "crossing" curves.The level ν = 4 of the L2Π state, which was discerned in the spectra of the heavier isotopes only, coincides in 14N16O with the level ν = 6 of C2Π and produces a strong three-level perturbation. The level, perturbed in this way, has the appearance of a separate electronic state in 14N16O and at one time was so identified.Many interaction energies are determined, and the new systems of "deper-turbed" levels are thoroughly discussed.

Infrared study of the X2Π ν = 0, 1, 2 levels of 14N16O. Preliminary results on the ν = 0, 1 levels of 14N17O, 14N18O, and 15N16O

1978 ◽  
Vol 56 (2) ◽  
pp. 251-265 ◽  
Author(s):  
C. Amiot ◽  
R. Bacis ◽  
G. Guelachvili
Keyword(s):  
High Resolution ◽  
Computer Program ◽  
Isotope Substitution ◽  
Molecular Constants ◽  
Infrared Study ◽  
Preliminary Results ◽  
Vibrational Levels ◽  
Fourier Spectra ◽  
Π State

The analysis of high resolution Fourier spectra (2.5 × 10−3 cm−1) led to accurate molecular constants for the vibrational levels ν = 0, 1, 2 of the X2Π state of 14N16O and of the levels ν = 0, 1 of the X2Π state of 14N17O, 14N18O, and 15N16O. A computer program has been written to directly reduce the data. It is shown that the expected variations for the different parameters with isotope substitution are well verified. Values of AJ(e) and γe are determined and discussed.

Picosecond fluorescence decays from vibrational levels in the S1(n,π*) state of pyridine vapor

1982 ◽  
Vol 92 (4) ◽  
pp. 421-424 ◽  
Author(s):  
Iwao Yamazaki ◽  
Toshiro Murao ◽  
Keitaro Yoshihara ◽  
Masahisa Fujita ◽  
Kazuyoshi Sushida ◽  
...  
Keyword(s):  
Vibrational Levels ◽  
Π State

Restriction of Access to Dark State: A New Mechanistic Model for Heteroatom-Containing AIE Systems

2019 ◽  
Author(s):  
Yujie Tu ◽  
Junkai Liu ◽  
Haoke Zhang ◽  
Qian Peng ◽  
Jacky W. Y. Lam ◽  
...  
Keyword(s):  
Excited States ◽  
Radiative Decay ◽  
Molecular Design ◽  
Mechanistic Model ◽  
Zinc Ion ◽  
Easy Access ◽  
Triplet States ◽  
Dark State ◽  
Ion Probe ◽  
Π State

Aggregation-induced emission (AIE) is an unusual photophysical phenomenon and provides an effective and advantageous strategy for the design of highly emissive materials in versatile applications such as sensing, imaging, and theragnosis. "Restriction of intramolecular motion" is the well-recognized working mechanism of AIE and have guided the molecular design of most AIE materials. However, it sometimes fails to be workable to some heteroatom-containing systems. Herein, in this work, we take more than one excited state into account and specify a mechanism –"restriction of access to dark state (RADS)" – to explain the AIE effect of heteroatom-containing molecules. An anthracene-based zinc ion probe named APA is chosen as the model compound, whose weak fluorescence in solution is ascribed to the easy access from the bright (π,π*) state to the closelying dark (n,π*) state caused by the strong vibronic coupling of the two excited states. By either metal complexation or aggregation, the dark state is less accessible due to the restriction of the molecular motion leading to the dark state and elevation of the dark state energy, thus the emission of the bright state is restored. RADS is found to be powerful in elucidating the photophysics of AIE materials with excited states which favor non-radiative decay, including overlap-forbidden states such as (n,π*) and CT states, spin-forbidden triplet states, which commonly exist in heteroatom-containing molecules.

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