High-resolution spectroscopy with a CCD array detector: application to the 2880 Å emission band system in I2

1993 ◽  
Vol 71 (10) ◽  
pp. 1645-1654 ◽  
Author(s):  
Joel Tellinghuisen
Keyword(s):  
High Resolution Spectroscopy ◽  
Spectroscopic Constants ◽  
Lower State ◽  
Array Detector ◽  
Weakly Bound ◽  
Ccd Array ◽  
Vibrational Levels ◽  
Discharge Spectrum ◽  
Absolute Energy ◽  
Text Component

The 2880 Å system in the Tesla discharge spectrum of I2 in Ar is reexamined using a CCD array detector to record spectra for both 127I2 and 129I2. This charge-transfer transition terminates on a weakly bound valence state, giving a highly congested spectrum with fine violet-degraded band structure barely perceivable on a pseudocontinuous background. The superior signal-to-noise capabilities of the array detector permit a great improvement in the precision and number of measured bandheads, as compared with previous results obtained from photographically recorded spectra. The new data span a larger range of vibrational levels in the lower state and lead to a change in the previous ν″ numbering by −3 units. Both states can now be located precisely on the absolute energy axis through least-squares fits in which the lower state energy is represented as a near-dissociation expansion. The primary spectroscopic constants (cm−1) are [Formula: see text] [Formula: see text] [Formula: see text] [Formula: see text] [Formula: see text] [Formula: see text] The lower state has a dissociation energy of 287.5 cm−1 and supports 35 bound levels, subject, however, to possible further revision due to a remaining uncertainty of 1 unit in the ν″ numbering. The previous tentative electronic assignment of this system remains in effect: The upper state is likely the [Formula: see text] state that correlates with I−(1S) + I+(3P1), while the lower state is the [Formula: see text] component of the lowest valence 3Πu multiplet.

High-resolution spectroscopy with a CCD array detector

1994 ◽  
Vol 231 (4-6) ◽  
pp. 515-520 ◽  
Author(s):  
Jason O. Clevenger ◽  
Joel Tellinghuisen
Keyword(s):  
High Resolution ◽  
High Resolution Spectroscopy ◽  
Array Detector ◽  
Ccd Array

Characterization of the shallow state of iodine chloride

1984 ◽  
Vol 62 (12) ◽  
pp. 1947-1953 ◽  
Author(s):  
J. C. D. Brand ◽  
D. Bussières ◽  
A. R. Hoy ◽  
S. M. Jaywant
Keyword(s):  
Ground State ◽  
Spectroscopic Constants ◽  
Interaction Matrix ◽  
Electronic Interaction ◽  
Weakly Bound ◽  
Interaction Matrix Element ◽  
Vibrational Levels ◽  
State 1 ◽  
Shallow State

A weakly bound Ω = 1 state of ICl, [Formula: see text], which converges to the ground state 1(2P3/2) + Cl(2P3/2) of the separated atoms, has been identified and characterized. Spectroscopic constants of this state are Te = 17 338.0(13), ωe = 32.85(48), ωexe = 1.272(40), 103Be = 38.2(13), 104αe = 8.89(34), 105γe = −8.1(20) cm−1, and re = 4.01(6) Å. The dissociation energy De = 219.6 cm−1 is consistent with the value predicted for a Morse function, [Formula: see text]. Transitions [Formula: see text] are allowed owing to homogeneous coupling between ã and the well-defined A(3π1) state; in fact, at medium-long range (r = 6–6.5 Å, D–Gν = 20–30 cm−1), the diabatic ã and A curves cross at a small angle. Principal features of the crossing are explained if the electronic interaction matrix element is ca. 4 cm−1, corresponding to weak coupling. Heterogeneous perturbations of the A and ã states in the range D–Gν < 200 cm−1 are attributed to coupling with high vibrational levels of the ground state X(1Σ+).

Theoretical study with rovibrational and electronic transitionmoment calculation of the ion LiCs+

2006 ◽  
Vol 84 (11) ◽  
pp. 959-971 ◽  
Author(s):  
M Korek ◽  
A M Moghrabi ◽  
A R Allouche ◽  
M Aubert Frécon
Keyword(s):  
Internuclear Distance ◽  
Bound States ◽  
Dipole Moments ◽  
Basis Sets ◽  
Spectroscopic Constants ◽  
Gaussian Basis Sets ◽  
Transition Dipole ◽  
Vibrational Levels ◽  
Moment Functions ◽  
Dependent Polarization

For the molecular ion LiCs+ the potential energy are calculated for the 39 lowest molecular states of symmetries 2Σ+, 2Π, 2Δ, and Ω = 1/2, 3/2, 5/2. Using an ab initio method, the calculation is based on nonempirical pseudopotentials and parameterized [Formula: see text]-dependent polarization potentials. Gaussian basis sets are used for both atoms and spin-orbit effects are taken into account. The spectroscopic constants for 20 states are calculated by fitting the calculated energy values to a polynomial in terms of the internuclear distance r. Through the canonical functions approach, the eigenvalue Ev, the abscissas of the corresponding turning points (rmin and rmax), and the rotational constants Bv are calculated for up to 44 vibrational levels for four bound states. Using the same approach the dipole moment functions, the corresponding matrix elements, and the transition dipole moments are calculated for the bound states (1)2Σ+, (2)2Σ+, and (1)2Π. The comparison of the present results with those available in literature for the ground state shows a very good agreement. Extensive tables of energy values versus internuclear distance are displayed at the following address: http://lasim.univ-lyon1.fr/allouche/licsso.html.PACS Nos.: 31.15.Ar, 31.25.–v, 31.25.Nj

The high-resolution spectroscopy of dissociating molecules

1990 ◽  
Vol 332 (1625) ◽  
pp. 297-307 ◽  
Keyword(s):  
High Resolution ◽  
Energy Flow ◽  
Energy State ◽  
Reaction Dynamics ◽  
Theoretical Models ◽  
Spectroscopic Studies ◽  
High Resolution Spectroscopy ◽  
Bond Breaking ◽  
Vibrational Levels ◽  
Dynamical Constraints

Results from spectroscopic studies of the vibrational levels of dissociating molecules and from state-selected, state-resolved photofragmentation spectroscopy are presented. The extent of energy flow among the modes of a molecule is explored through the couplings, or lack thereof, revealed by high-resolution spectroscopy. The dynamics of energy flow during bond breaking are revealed by photofragment excitation spectroscopy and by product energy state distributions. These completely resolved data provide sensitive tests of dynamical constraints such as vibrational or rotational adiabaticity and thus of theoretical models for unimolecular reaction dynamics.

Experimental Study of Low Energy e-O2 Collision Processes

1971 ◽  
Vol 26 (10) ◽  
pp. 1617-1625 ◽  
Author(s):  
F. Linder ◽  
H. Schmidt
Keyword(s):  
Angular Dependence ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
Resonance Scattering ◽  
Spectroscopic Constants ◽  
Extended Model ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
The Cross ◽  
Electronic Ground

Abstract Elastic scattering, vibrational excitation to v=1, 2, 3, 4 of the electronic ground state, and electronic excitation to the states a1Δ g and b1Σg+ of O2 have been measured in a crossed beam apparatus for collision energies from nearly 0 eV to 4 eV. Differential and integral cross sections have been determined and calibrated on an absolute scale. From 15 vibrational levels of O2-, which could be observed as resonances in the cross sections, the spectroscopic constants for the vibrational structure of O2- have been derived: ωe = 135 meV and ωeχe = 1 meV. The cross sections for vibrational excitation have the order of 10-18 cm2. eV for the larger resonance peaks. Detailed cross sections have been listed in Table 1. The half width of the resonance can be estimated to Γ ≈ 0.5 meV, which corresponds to a lifetime tof 10-12 sec for the O2- states. The angular dependence of pure resonance scattering is rather flat and not in accordance with the simplest theoretical model. An analysis of the angular dependence and of the rotational structure of the resonance in a somewhat extended model have been performed. - No electronically excited O2-states could be detected in the energy range up to 3 eV.

The Emission Spectrum of PtO between 3800 and 4500 Å

1975 ◽  
Vol 53 (19) ◽  
pp. 1991-1999 ◽  
Author(s):  
Rosemary Scullman ◽  
Ulf Sassenberg ◽  
Christer Nilsson
Keyword(s):  
Emission Spectrum ◽  
Ground State ◽  
Lower State ◽  
Vibrational Levels ◽  
New System

A new system belonging to the emission spectrum of PtO has been found in the region of 3800–4500 Å. This system has the earlier known X1Σ ground state as the lower state and a hitherto unknown 1Σ state, here designated the D1Σ state, as the upper state. The four lowest vibrational levels of the D1Σ state were rotationally analyzed. Of these levels, the [Formula: see text] level seems to be unperturbed although the v′ = 1, 2, and 3 levels are strongly perturbed.

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.

The 7500 to 4500 Å absorption system of the free HCO radical

1955 ◽  
Vol 233 (1192) ◽  
pp. 34-54 ◽  
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Flash Photolysis ◽  
Lower State ◽  
Absorption System ◽  
Molecular Plane ◽  
Bending Mode ◽  
Vibrational Levels ◽  
Other Substances ◽  
Low Dispersion

A fairly extensive absorption spectrum o f the free HCO radical produced by flash photolysis of acetaldehyde and other substances has been investigated with long absorbing paths and under high resolution. The corresponding DCO spectrum has also been studied. The absorption spectrum consists of simple bands with P, Q and R branches. It is shown that the molecule is linear in the upper state, but bent in the lower state with an angle of about 120° and a CO bond length of approximately 1.20 Å. Rotational constants of HCO and DCO in both upper and lower states have been derived. Various arguments based on the high-resolution measurements lead to the conclusion that the main progression of bands corresponds to transitions to the vibrational levels of the upper state with even v' 2 (the vibrational quantum number of the bending mode). This conclusion is confirmed by the observation under low dispersion of some of the intermediate bands with odd v’ 2 which are diffuse and therefore not easily recognizable under high resolution. Apparently all levels of the upper state with l≠0 are predissociated. The type of the electronic transition is shown to be 2 Σ+ ← 2 A”, that is, the transition moment is perpendicular to the molecular plane. The lower state cannot arise from normal CO and H.

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