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.

The Lyman and Werner Bands of Deuterium

1973 ◽  
Vol 51 (9) ◽  
pp. 867-887 ◽  
Author(s):  
H. Bredohl ◽  
G. Herzberg
Keyword(s):  
High Resolution ◽  
Ab Initio Calculations ◽  
Vibrational Level ◽  
Ground State ◽  
Electronic Excitation ◽  
Theoretical Calculations ◽  
Dissociation Limit ◽  
Excitation Energies ◽  
Vibrational Levels ◽  
Theory And Experiment

The Lyman and Werner bands of D2 have been measured under high resolution and their analysis has been extended. From this analysis the rotational and vibrational levels of the ground state of D2 have been evaluated up to the last vibrational level ν = 21 which lies only 2 cm−1 below the dissociation limit. The deviations of the observed ΔG(ν + 1/2) and Bv values from theoretical values given by Kolos and Wolniewicz on the basis of ab initio calculations are very small but systematic and are probably due to the neglect of nonadiabatic corrections in the theoretical calculations. Similar comparisons have been made for the lower vibrational levels of the B1Σu+ and C1Πu− states. Here the differences between theory and experiment are somewhat larger. The observed electronic excitation energies agree with the theoretical ones within 15 cm−1 for 1Σu+ and 8 cm−1 for 1Πu−.

The carbon monoxide flame bands

1963 ◽  
Vol 275 (1362) ◽  
pp. 431-446 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Excited State ◽  
High Resolution ◽  
Energy Level ◽  
Vibrational Level ◽  
Ground State ◽  
Fermi Resonance ◽  
Absorption System ◽  
Weak Absorption ◽  
Vibrational Levels

The carbon monoxide flame bands have been photographed under high resolution from an afterglow source. Bands in the wavelength range 3100 to 3800 Å show a pattern which has been reproduced by calculations of the energies of high vibrational levels of the ground state of CO 2 . The structure of this energy level pattern is strongly affected by extensive Fermi resonance in the 1 Σ + g state. The spectrum is emitted by excited CO 2 molecules which radiate to the ground state from the lowest vibrational level and from the v ´ 2 = 1 level of a B 2 state. This excited state lies approximately 46 000 cm -1 above the lowest level of the ground state, an d has an OCO angle of 122 + 2° and a CO bond length of 1*246 ± 0*008 Å. Combination of these results with the work of other authors shows that the excited state is a 1 B 2 state, and that the carbon monoxide flame bands are associated with the weak absorption system of CO 2 at 1475 Å.

The Absorption Spectrum of D2 from 1100 to 840 Å

1974 ◽  
Vol 52 (12) ◽  
pp. 1110-1136 ◽  
Author(s):  
I. Dabrowski ◽  
G. Herzberg
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Detailed Comparison ◽  
Electronic Energy ◽  
Dissociation Limit ◽  
Convergence Error ◽  
Vibrational Levels ◽  
Vibrational Constants

The absorption spectrum of D2 has been studied in absorption at high resolution (0.254 Å/mm) in the region 1100 to 840 Å. The three band systems B1Σu+ ← X1Σg+ (Lyman bands), B′ 1Σu+ ← X1Σg+ and C1Πu ← X1Σg (Werner bands) have been measured right up to the dissociation limit. New improved values of the rotational and vibrational constants in the three upper states have been derived. By comparing the electronic energy differences Tc thus obtained with the corresponding values for H2 fairly precise values for the electronic isotope shifts for the B–X and C–X systems have been determined (+ 2.8 and −7.4 cm−1 respectively). In this connection two gaps in the knowledge of the absorption spectrum of H2 have been filled: the Lyman bands with ν′ = 5–16 and the Werner bands with ν′ = 0–4 (see Appendix). A detailed comparison is made of the observed vibrational levels and the observed Bν values of D2 with those derived from ab initio calculations based on the Kotos and Wolniewicz' potential functions. From the observed electronic isotope shift the adiabatic corrections can be estimated near the minimum. For the B state these estimates agree very well with the ab initio calculations. The remaining differences between observation and theory are partly due to lack of convergence of the Born–Oppenheimer calculation, partly to the neglect of nonadiabatic corrections. The convergence error near minimum is estimated to be 5.1 cm−1 for the B state and 1.2 cm−1 for the C state.

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.

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.

K-shell photoionization of Li, Be+ and B2+

2016 ◽  
Vol 30 (15) ◽  
pp. 1650204 ◽  
Author(s):  
Jun Li ◽  
Jian Dang Liu ◽  
Song Bin Zhang ◽  
Bang Jiao Ye
Keyword(s):  
High Resolution ◽  
Light Source ◽  
Cross Sections ◽  
Ground State ◽  
Matrix Method ◽  
Theoretical Calculations ◽  
Metastable States ◽  
The Core ◽  
Advanced Light Source ◽  
State Formula

K-shell photoionization (PI) of Li, Be[Formula: see text] and B[Formula: see text] from ground state [Formula: see text] have been studied by using the [Formula: see text]-matrix method with pseudostates. The K-shell PI process is featured with the contributions from the core-excited metastable states or dominated by the Auger states 2Po. The resonant parameters of the Auger states 2Po and the PI cross-sections have been calculated and compared with the available experimental and theoretical works. Our results agree very well with that of the published works. It is worth noting that compared with previous theoretical calculations, our results of B[Formula: see text] show better agreements with the latest high-resolution advanced light source measurements [A. Müller et al., J. Phys. B 43 (2010) 135602].

Spectrum of AsS. I. Analysis of the A′2Π3/2–X2Π3/2 Band System

1971 ◽  
Vol 49 (10) ◽  
pp. 1249-1254 ◽  
Author(s):  
Midori Shimauchi
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Ground State ◽  
Band System ◽  
Vibrational Analysis ◽  
Quartz Tube ◽  
Rotational Analysis ◽  
Vibrational Constants

The emission spectrum of the AsS radical, excited in a quartz tube by a 2450 MHz oscillator, was photographed on a high resolution spectrograph from 2450 to 6900 Å. Seven bands around 6000 Å showing clear rotational structures were chosen for the first rotational analysis of the AsS spectrum. The bands were found to arise from a 2Π3/2–2Π3/2 transition. The rotational and vibrational constants of the two states derived from the present work are consistent with the previous vibrational analysis of the A′2Π3/2–X2Π3/2 system. The constants of the upper doublet component of the ground state, X2Π3/2, are ωe = 562.40 cm−1, ωexe = 2.02 cm−1, re = 2.0216 Å; the constants of the A′2Π3/2 state are ΔG′(1/2) = 403.37 cm−1, ν0,0 = 18 621.21 cm−1, re = 2.2500 Å.

High resolution absorption spectrum of nitric oxide (NO) in the region of the first ionization limit

1976 ◽  
Vol 54 (20) ◽  
pp. 2074-2092 ◽  
Author(s):  
E. Miescher
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Ionization Energy ◽  
Dissociation Limit ◽  
Matrix Elements ◽  
Rydberg Series ◽  
Isotopic Species ◽  
Vibrational Levels ◽  
Energy Formula ◽  
Ionization Limit

The absorption spectrum of cold NO gas has been photographed at high resolution between 1400 and 1250 Å for two isotopic species. Resolved bands of the Rydberg series converging to vibrational levels of the 1Σ+ ground state of NO+ are studied. They include nf–X bands up to n = 15 and ns–X bands up to n = 11, all of which show sharp rotational structure. The higher members of the np–X series are generally very diffuse with only npσ being sufficiently sharp to show broadened rotational lines. Also mostly diffuse are the ndδ–X bands. The bands ndσ, π–X are not observed. The rapidly (n−3) narrowing structure of the nf complexes is discussed and the ionization energy [Formula: see text] accurately determined by extrapolation of selected rotational lines. Interactions between Rydberg states are numerous, s ~ d mixing produces a strong effect above n = 6 when (n + 1)s levels fuse with nl levels into 'supercomplexes'. Matrix elements are given for observed 8f ~ 9s and 6f ~ 6dδ interactions.Valence levels are not observed above the ionization energy, except for the repulsive state A′2Σ+ arising from the first dissociation limit and seemingly assuming Rydberg character at molecular internuclear distance. Observed anomalies are qualitatively discussed.

Absorption spectrum of the Mg2 molecule

1970 ◽  
Vol 48 (7) ◽  
pp. 901-914 ◽  
Author(s):  
W. J. Balfour ◽  
A. E. Douglas
Keyword(s):  
Absorption Spectrum ◽  
Excited State ◽  
High Resolution ◽  
Potential Energy ◽  
Dissociation Energy ◽  
Ground State ◽  
Potential Energy Curve ◽  
Energy Curve ◽  
Vibrational Constants

The absorption spectrum of the Mg2 molecule, which occurs in a furnace containing Mg vapor, has been photographed with a high resolution spectrograph. The rotational structures of the bands have been analyzed and the rotational and vibrational constants of the two states determined. The bands are found to arise from a 1Σ–1Σ transition between a very lightly bonded ground state and a more stable excited state. The R.K.R. potential energy curve of the ground state, which has a dissociation energy of 399 cm−1, has been determined. The more important constants of the ground state are ωe = 51.12 cm−1, ωexe = 1.64 cm−1, re = 3.890 Å and those of the upper state are ωe = 190.61 cm−1, ωexe = 1.14 cm−1, re = 3.082 Å.

Sign in / Sign up

Export Citation Format

Share Document