Calculated Rydberg States of the PO Molecule

1972 ◽  
Vol 50 (7) ◽  
pp. 692-699 ◽  
Author(s):  
F. Ackermann ◽  
H. Lefebvre-Brion ◽  
A. L. Roche
Keyword(s):  
Ionization Potential ◽  
Ground State ◽  
Valence State ◽  
Rydberg States ◽  
Electron Excitation ◽  
The Other ◽  
Molecular Ion ◽  
A Value ◽  
Good For ◽  
Lcao Mo

The Rydberg States of the PO molecule, converging to the ground state of the PO+ ion, are calculated using the LCAO–MO SCF orbitals of the molecular ion core. An adjustment between the observed and calculated values for the energy of the first Rydberg A2Σ+ state gives a value of about 66 400 cm−1 for the ionization potential of PO. The agreement between the experimental and calculated values is very good for the other observed Rydberg states. In the 5300–3800 Å region, no more than four 2Σ+ Rydberg states are expected, which supports the "deperturbation" procedure carried out by Verma. A comparison is made between the p, d, and ƒ complexes in PO and NO. The B2Σ+ state appears to be a valence state corresponding to the electron excitation from an antibonding (vπ)* orbital to a weakly antibonding (uσ)* orbital.

Emission Spectrum of the PO Molecule. Part II.2Σ–2Σ Transitions

1971 ◽  
Vol 49 (24) ◽  
pp. 3180-3200 ◽  
Author(s):  
R. D. Verma ◽  
M. N. Dixit ◽  
S. S. Jois ◽  
S. Nagaraj ◽  
S. R. Singhal
Keyword(s):  
Emission Spectrum ◽  
Ionization Potential ◽  
Dissociation Energy ◽  
Ground State ◽  
Rydberg States ◽  
Electronic States ◽  
Electronic Transitions ◽  
A Value ◽  
Upper Limit ◽  
First Ionization Potential

Rotational structure of emission bands of the PO molecule in the region 5300–3800 Å is analyzed. The spectrum is attributed to 5 electronic transitions A2Σ+–B2Σ+, F2Σ+–B2Σ+, G2Σ+–B2Σ+, H2Σ+–B2Σ+, and I2Σ+–B2Σ+, where F, G, H, and I are the new electronic states and A and B are the upper states of the well-known γ and β bands respectively. Practically all the new 2Σ states are found to be perturbed. A qualitative account of these perturbations together with a deperturbation of certain levels is given. A number of cases of predissociation are also observed. This predissociation is attributed to the presence of 4Πi, and A′2Σ+ states, which dissociate to the ground state atomic products. From this an upper limit of the dissociation energy of the ground state of PO is determined to be D0 = 49 536 cm−1. The A, D, E, G, H, and I states of this molecule are assigned as Rydberg states corresponding to the σ4s, π4p, δ3d, σ4p, σ3d, and σ5s orbitals, respectively. From them a value of 67 570 cm−1 is evaluated for the first ionization potential of PO. All the electronic states established for this molecule are described in terms of electron configurations.

Rotational Structure in Some Higher Excited States of the GeF Molecule

1974 ◽  
Vol 52 (15) ◽  
pp. 1458-1475 ◽  
Author(s):  
R. W. Martin ◽  
A. J. Merer
Keyword(s):  
Emission Spectrum ◽  
Excited States ◽  
Ground State ◽  
Valence State ◽  
Rydberg States ◽  
The Other ◽  
Electronic Transitions ◽  
Lower State ◽  
High Dispersion ◽  
Higher Excited States

The weaker electronic transitions in the region 2000–9000 Å in the emission spectrum of GeF have been photographed at high dispersion; three new transitions with the A2Σ+ state as lower state have been discovered, and the various systems near 2100 and 8600 Å have been reassigned. The spectra have been explained in terms of six excited states lying between 40 000 and 50 000 cm−1 above the ground state, and representative bands involving all six have been analyzed rotationally. Five of these excited states are Rydberg states (5pσ, 5pπ, 4dπ, 4dδ, and 6sσ), and the other is the σπ22Δ valence state; this latter interacts strongly with the 4dδ 2Δ state.

Rydberg series and autoionization resonances in the Y I absorption spectrum

1973 ◽  
Vol 333 (1592) ◽  
pp. 17-24 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Ionization Potential ◽  
Excited States ◽  
Spectral Range ◽  
Ground State ◽  
Rydberg Series ◽  
A Value ◽  
Doublet Ground State ◽  
Ionization Limit ◽  
First Ionization Potential

The absorption spectrum of yttrium vapour has been photographed in the spectral range 1650 to 2250 À, with a 10 m spectrograph. Series of autoionization resonances, which converge on excited states of the Y + ion have been identified, as combinations with the doublet ground-state of Y I , 5s 2 4d 2 D 3/2 , 5/2 . Although the lines of these series show broadened and often asymmetrical profiles, the lines are sufficiently well defined to fix a value for the first ionization potential of Y I , which differs from the previously accepted value by approximately 2500 cm -1 . In addition, approximately 400 new Y I lines, which involve excited levels below the first ionization limit of Y I , namely 4s 2 1 S o , have been found. The majority of these are unclassifiable at present but, the value for the first ionization-potential being known from the resonances above-mentioned, two series of the character 5s 2 4d 2 D 3/2 , 5/2 -5s 2 nf 2 F o have been identified. In addition to the identifications of series, 152 new lines below the 5s 2 1 S o limit identify 76 new levels of Y I , of odd parity.

New electronic transitions of the C2 molecule in absorption in the vacuum ultraviolet region

1969 ◽  
Vol 47 (24) ◽  
pp. 2735-2743 ◽  
Author(s):  
G. Herzberg ◽  
A. Lagerqvist ◽  
C. Malmberg
Keyword(s):  
Ground State ◽  
Vacuum Ultraviolet ◽  
Rydberg States ◽  
The Other ◽  
Electronic Transitions ◽  
Lower State ◽  
Ultraviolet Region ◽  
New States ◽  
Vacuum Ultraviolet Region ◽  
Vibrational Constants

Three new electronic transitions of the C2 molecule have been observed in absorption in the region 1300–1450 Å. The system of shortest wavelength is readily identified as a 1Πu–1Σg+ transition; the lower state is the ground state X1Σg+ of the molecule. The other two systems arise by absorption from the low-lying a3Πu state; the upper states are new 3Σg− and 3Δg states. Rotational and vibrational constants of the three new states have been determined. The new states are Rydberg states. Their correlation to the separated atoms is briefly discussed.

The Logical Consequence of Fitting Attitudes

2021 ◽  
pp. 119-130
Author(s):  
Toni Rønnow-Rasmussen
Keyword(s):  
Logical Consequence ◽  
The Other ◽  
Bad News ◽  
Challenging Problem ◽  
Consequence Argument ◽  
Fitting Attitudes ◽  
A Value ◽  
Good For

Any fitting-attitude (FA) analysis which understands value ultimately in terms of reasons and pro- and con-attitudes will have limited wiggle room if it is to respect the kind of radical division between good and good-for that earlier chapters have outlined. Essentially, its proponents can either introduce two different normative notions, one relating to good and the other to good-for, or distinguish two kinds of attitude, one corresponding to the analysis of good and the other corresponding to the analysis of good-for. ‘The Logical Consequence of Fitting Attitudes’ outlines why the latter, ‘attitudinal’ approach is preferable. Unfortunately, the attitudinal approach faces a challenging problem: the logical consequence argument. According to it, the attitudinal approach has the unwelcome consequence that whatever is good for someone is also, necessarily, non-relationally good. That is bad news—especially if you are a value dualist. The next chapter (Chap. 8) is devoted to resolving this issue.

Comments on the paper by A. D. Walsh

1951 ◽  
Vol 207 (1088) ◽  
pp. 31-32 ◽  
Keyword(s):  
Ionization Potential ◽  
Ground State ◽  
Valence State ◽  
Periodic Table ◽  
Direct Relationship ◽  
Ionization Potentials ◽  
Electron Affinities ◽  
Theoretical Justification ◽  
Left Hand ◽  
The Right

Theoretical justification for a relationship between ionization potential ( I ) and electronegativity ( x ) rests in the equation derived by Mulliken (1934, 1949), viz.: X = I + E / 2 where E is the electron affinity. Elements situate on the left-hand side of the Periodic Table have small E values, so that in these cases a direct relationship between x and I might be anticipated. On the right-hand side of the Periodic Table, the electron affinities may be appreciable, and for example in the halogens, are of the order 3 to 4 eV. The neglect of the term in E in these instances represents a serious departure from Mulliken’s equation. It is furthermore important to stress that the values of I which apply in the Mulliken equation are ‘valence-state’ ionization potentials, and are not in general to be identified with the first ionization potentials of the elements, which Walsh has employed. The relationships observed by Walsh might, in consequence, be misleading in cases where the ionization potential of the ground-state of an atom is far removed (in energy) from the ionization potential of the atom in its appropriate valence-state (e.g. Zn, Cd, Hg).

scholarly journals STABILITY OF GROUND STATES IN SECTORS AND ITS APPLICATION TO THE WIGNER–WEISSKOPF MODEL

2001 ◽  
Vol 13 (04) ◽  
pp. 513-528 ◽  
Author(s):  
ASAO ARAI ◽  
MASAO HIROKAWA
Keyword(s):  
Excited State ◽  
Scalar Field ◽  
Ground State ◽  
Adjoint Operator ◽  
Ground States ◽  
The Other ◽  
Coupling Constant ◽  
A Value ◽  
First Excited State ◽  
The One

We consider two kinds of stability (under a perturbation) of the ground state of a self-adjoint operator: the one is concerned with the sector to which the ground state belongs and the other is about the uniqueness of the ground state. As an application to the Wigner–Weisskopf model which describes one mode fermion coupled to a quantum scalar field, we prove in the massive case the following: (a) For a value of the coupling constant, the Wigner–Weisskopf model has degenerate ground states; (b) for a value of the coupling constant, the Wigner–Weisskopf model has a first excited state with energy level below the bottom of the essential spectrum. These phenomena are nonperturbative.

The effect of fluorine on the electronic spectra and ionization potentials of molecules

1960 ◽  
Vol 258 (1295) ◽  
pp. 459-469 ◽  
Keyword(s):  
Ionization Potential ◽  
Ground State ◽  
Inductive Effect ◽  
Opposite Sign ◽  
Alkyl Halides ◽  
Ionization Potentials ◽  
Molecular Ion ◽  
Resonance Effects ◽  
Inductive Effects ◽  
Resonance Stabilization

The effect of substituents on the spectra and ionization potentials of electrons in chromophoric groups can in a general way be divided into two major contributions, namely, ( a ) inductive effects which act mainly by changing the binding of electrons in the ground state, and ( b ) resonance effects which stabilize the molecular ion. When the substituent is a fluorine atom these effects are large but of opposite sign. The magnitude of the inductive effect is shown to be in some cases as much as several electron volts by considering sets of molecules where resonance stabilization of the molecular ion is negligible, for example, hydrocarbons and their perfluoroderivatives, NH 3 and NF 3 , the perfluoromethyl halides, etc. In other classes of molecules, such as the trifluoromethyl radicals, the fluorinated ethylenes and aromatics, large resonance stabilization of the molecular ion occurs along with the inductive effect and as these are of opposite sign, relatively small changes of ionization potential result from the substitution. The study of the dependence of increases of ionization potential due to inductive effects on the distance of the substituted fluorine from a chromophore shows how this is reduced as the separation increases. Many of the longer wavelength bands of various chromophores show shifts on substitution which are in the opposite direction to the changes which occur in the ionization potential. It is suggested that these can in many cases be attributed to the different spatial dependence of resonance and inductive effects. The interplay of this spatial variation and the dimensions of the upper orbital, especially when this has a large overlap with the substituting group, can produce energy changes in the excited orbitals which make the bands appear to behave anomolously on substitution. New values for the ionization potentials of the fluorinated ethylenes, aromatics and alkyl halides are given.

The absorption spectrum of diatomic phosphorus between 1370 and 600 Å

1975 ◽  
Vol 342 (1628) ◽  
pp. 93-111 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Ionization Potential ◽  
Dissociation Energy ◽  
Ground State ◽  
Molecular Orbitals ◽  
The Other ◽  
Ultraviolet Absorption Spectrum ◽  
Rydberg Series ◽  
Far Ultraviolet ◽  
First Ionization Potential

Nine Rydberg series have been observed in the far ultraviolet absorption spectrum of P 2 . Four of these converge to the.(5σ g ) 2 (2π u ) 3 , 2II u (inv.) state of the ion which is established as being the ground state; four to the low-lying ...(5σ g ) (2π u ) 4 , A 2 Ʃ g + state and one to a newly identified (5σ g ) (2π u )3 2πg, F 2 Ʃ + u state. The first ionization potential is found to be 85 229 ± 15 cm-1 (10.567 ± 0.002eV), which is the limit corresponding to the upper component (2II1/2 ) of the inverted X 2II u state. The other limits are observed at 87 179 + 2cm -1 (A 2 Ʃ + g ) and 125 225 ± 10cm -1 (F 2 Ʃ + u ). The series have been interpreted in terms of molecular orbitals and are found to involve excitation of n sσ g , n dσ g , n dπ g and n dδ g for the X 2 II u core; n pπ u , n fσ u , and n fπ u for the A 2 Ʃ + g core and for the A 2 Ʃ + u core. The evaluation and identification of the series limits enables the relative positions of the states of P + 2 to be established. The dissociation energy of P + 2 is estimated to be 4.98 ± 0.01eV.

High resolution studies of electron excitation IV. The n = 3 states of helium

1977 ◽  
Vol 352 (1670) ◽  
pp. 419-428 ◽  
Keyword(s):  
Angular Momentum ◽  
High Resolution ◽  
Ionization Potential ◽  
Electron Excitation ◽  
Resonance Radiation ◽  
The Other ◽  
Threshold Values ◽  
Polarization Data ◽  
Polarization Functions

We present excitation and polarization functions for the n = 3 states of helium for energies between threshold and the ionization potential. In the case of the line at 501.6 nm (3 1 P-2 1 S) our polarization data is affected by the imprisonment of resonance radiation, but in the other cases our data is consistent with threshold values predicted by conservation of angular momentum. The excitation and polarization functions show considerable structure and we identify two of the major features which appear in all the functions as S and P resonances.

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