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.

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 absorption and emission spectra of HD in the vacuum ultraviolet

1976 ◽  
Vol 54 (5) ◽  
pp. 525-567 ◽  
Author(s):  
I. Dabrowski ◽  
G. Herzberg
Keyword(s):  
Absorption Spectrum ◽  
Ab Initio ◽  
Excited States ◽  
Vacuum Ultraviolet ◽  
Emission Spectra ◽  
Dissociation Limit ◽  
Infinite Mass ◽  
Ab Initio Theory ◽  
Vibrational Constants ◽  
Weak Transitions

The absorption spectrum of HD has been studied under high resolution in the vacuum ultraviolet to 840 Å, the emission spectrum to 1000 Å. The analysis of the latter gives accurate rotational constants and vibrational intervals of the ground state right up to the dissociation limit. Comparing these experimental data with calculations from ab initio theory, agreement to the same extent as was previously found for H2 and D2 is obtained. Extrapolation of the obs. – calc. values from H2 and D2 to infinite mass yields agreement with the recently revised theoretical values to within less than 0.1 for v < 7 and less than 0.5 cm−1 for the whole range of observed v values. The deviations for finite mass (H2 and D2) are clearly due to the non-adiabatic corrections neglected in the ab initio calculations. The results for HD are not halfway between H2 and D2 but are closer to H2. This apparent anomaly can be quantitatively accounted for, on the basis of recent calculations of Wolniewicz, by the effect of additional nonadiabatic corrections caused by the excited Σu states which in HD, unlike H2 and D2, can interact with the ground state.The rotational and vibrational constants of the excited states B1Σu+, C1Πu, and B′1Σu+ show somewhat larger deviations from ab initio values ranging for v0v from 5 to 120 cm−1, just as for H2 and D2. The electronic isotope shift of HD lies approximately half-way between the values of H2 and D2 as expected. In addition to the B–X, C–X, and B′–X systems the absorption spectrum of HD, unlike that of H2 and D2, shows an extensive progression of weak transitions to the double minimum state EF1Σg+ and a few very weak transitions to the G1Σg+ and I1Πg states. For the EF state both levels in the outer minimum (F) and levels above the maximum are observed. The correlation of the six excited states B, C, B′, EF, G, and I to the two close-lying dissociation limits corresponding to H + D* and H* + D is briefly discussed.

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.

High resolution absorption studies of the b1Πu ← X1Σg+ system of nitrogen

1969 ◽  
Vol 47 (5) ◽  
pp. 563-589 ◽  
Author(s):  
P. K. Carroll ◽  
C. P. Collins
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Triplet State ◽  
Rotational Structure ◽  
Dissociation Limit ◽  
Rydberg Series ◽  
Absorption Studies ◽  
Vibrational Levels ◽  
Single Transition ◽  
Made In

New high resolution studies of the absorption spectrum of N2 have been made in the region 1015–795 Å. Analyses are given of 25 non-Rydberg bands of the type 1Πu–X1Σg+. It is shown that all of these bands, which include the i, j, b, l, m, p, and q groups of Worley, together with several new bands not previously observed, can be assigned to a single transition the upper state of which is called b1Πu. The pronounced irregularities in the vibrational and rotational structure of the b state are attributed to a homogeneous interaction with the first member (n = 3) of the ---(3σg) npπu, 1Πu Rydberg series. This perturbation is discussed in the accompanying paper by Dressier who recognized its importance in the interpretation of the spectrum. Diffuseness in the rotational lines of several bands at lower ν was observed and is attributed to predissociation by a triplet state, probably the C′ 3Πu state which goes to the 4S + 2D dissociation limit. Three levels of the b state show measurable Λ-type doubling which can be interpreted as caused by interaction with vibrational levels of the first member (n = 4) of the --(3σg) npσu, 1Σu+ Rydberg series. The assignment of 28 non-Rydberg 1Σu+ levels, including the b′, g, f, r, s, and t "states", to a single 1Σu+ state which is called b′, is also briefly discussed.

The Lyman and Werner bands of H2

1984 ◽  
Vol 62 (12) ◽  
pp. 1639-1664 ◽  
Author(s):  
I. Dabrowski
Keyword(s):  
Ab Initio ◽  
Vacuum Ultraviolet ◽  
Energy Levels ◽  
Vibration Energy ◽  
Dissociation Limit ◽  
Convergence Error ◽  
Ab Initio Theory ◽  
Vibrational Levels ◽  
Low Energies ◽  
State Formula

The Lyman and Werner bands of H2 have been measured under high resolution in the vacuum ultraviolet from 1000 to 1650 Å. Flash discharge spectra, both in absorption and in emission, have allowed an extension of the analysis to include most of the rotation–vibration levels of the ground state ([Formula: see text], ν = 0 to 14, J = 0 to 29). The C1Πu state has been observed from ν = 0–13, and the [Formula: see text] state from ν = 0–17, including highly rotationally excited levels for ν = 0–6. The resulting rotation–vibration energy levels are accurate to 0.1 cm−1.The agreement between observation and ab initio theory is now very good. The deviations of the vibrational levels are very close to zero for low ν, but increase to 0.3 cm−1 for high ν. The ab initio calculations are somewhat less accurate for the rotational levels. The deviations are close to zero for low J, but increase to 4 cm−1 for high J, that is, for energy levels close to the dissociation limit. It can also be seen that the convergence error in the Born–Oppenheimer calculation is small (~0.1 cm−1) at low energies, but approaches 1 cm−1 near the dissociation limit.

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−.

Inversion Motion and S1Equilibrium Geometry of 4-Fluoroaniline:  Molecular Beam High-Resolution Spectroscopy and ab Initio Calculations

1999 ◽  
Vol 103 (45) ◽  
pp. 8946-8951 ◽  
Author(s):  
M. Becucci ◽  
E. Castellucci ◽  
I. López-Tocón ◽  
G. Pietraperzia ◽  
P. R. Salvi ◽  
...  
Keyword(s):  
High Resolution ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Molecular Beam ◽  
High Resolution Spectroscopy

Gas-phase detection of the FCO2 radical by millimeter wave and high resolution infrared spectroscopy assisted by ab initio calculations

2003 ◽  
Vol 118 (3) ◽  
pp. 1214-1220 ◽  
Author(s):  
Zdeněk Zelinger ◽  
Pascal Dréan ◽  
Adam Walters ◽  
Juan Ramon Avilès Moreno ◽  
Marcel Bogey ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
High Resolution ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Gas Phase ◽  
Millimeter Wave ◽  
Phase Detection
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