A New Method for Band Contour Analysis with Application to the Spectrum of Pyridine-4-d1

1973 ◽  
Vol 51 (10) ◽  
pp. 1031-1038 ◽  
Author(s):  
F. W. Birss ◽  
S. D. Colson ◽  
D. A. Ramsay
Keyword(s):  
Excited State ◽  
Ground State ◽  
Energy Levels ◽  
New Method ◽  
Contour Analysis ◽  
Rotational Constants ◽  
Near Ultraviolet ◽  
Asymmetric Rotor ◽  
Band Contour ◽  
Molecular Dimensions

A new method for generating band contours is described which is both rapid and accurate. One contour is generated from another using the differentials of the energy levels with respect to the rotational constants, thus avoiding the need for repeated diagonalization of the asymmetric rotor matrices.The method is applied to two C-type bands in the near ultraviolet π*–n transition of pyridine-4-d1. For the 0–0 band the following constants are obtained: A′ = 0.19843 ± 0.00008 cm−1, B′ = 0.17957 ± 0.00008 cm−1, C′ = 0.09426 ± 0.00020 cm−1, ν0 = 34 800.31 cm−1. These constants are slightly smaller than the ground state constants, indicating a very small increase in the molecular dimensions in the excited state.

Analysis of the naphthalene vapour absorption bands at 3200Å. I. Naphthalene h -8

1961 ◽  
Vol 253 (1035) ◽  
pp. 543-568 ◽  
Keyword(s):  
Ground State ◽  
Energy Levels ◽  
Rotational Energy ◽  
Absorption Bands ◽  
Type Band ◽  
State Frequency ◽  
Asymmetric Rotor ◽  
Band Contour ◽  
Direction Of Polarization ◽  
First Time

The absorption bands of naphthalene vapour near 3200 A have been measured at medium and high resolution and analyzed for the first time. The bands have strong heads weakly degraded to the red. The direction of polarization of the 0—0 pure electronic transition has been identified from the band contour of the corresponding band, which shows a single intense maximum. Calculations of rotational energy levels confirm that this is a quasi-parallel A -type band of the asymmetric rotor, with polarization along the longer in-plane molecular axis. Accompanying the electronically allowed band is a set of stronger vibrationally induced bands, which show doubled intensity maxima. From approximate calculations of contours it is confirmed that these are quasi-perpendicular B -type bands, polarized along the shorter in-plane axis. The electronic assignment B 2u <- A g , long-axis polarized, agrees with McClure’s assignment from the spectrum of naphthalene embedded in durene crystals. The use of rotational band contours for assigning transitions is novel in larger molecules and seems likely to be applicable rather widely. A hitherto unrecorded ground-state frequency 506 cm<super>-1</super> of species b 3g has been identified, and a number of other ground and excited-state frequencies confirmed and assigned, or recorded for the first time.

The analysis of a 2 A 1 - 2 B 1 electronic band system of the AsH 2 and AsD 2 radicals

1968 ◽  
Vol 305 (1481) ◽  
pp. 271-290 ◽  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Flash Photolysis ◽  
Band System ◽  
Valence Angle ◽  
Electronic Transitions ◽  
Doublet State ◽  
Electronic Band ◽  
Asymmetric Rotor ◽  
Asymmetric Top

Two new band systems have been observed in absorption following flash photolysis of AsH 3 and AsD 3 , and are assigned to 2 A 1 - 2 B 1 electronic transitions of AsH 2 and AsD 2 . The origins of both systems are at 19905 cm -1 . The bands have the complex rotational structure associated with an asymmetric rotor. Rotational analyses have been carried out for three bands of the AsH 2 spectrum, leading to the following molecular parameters: ground state, r" 0 = 1.518 Å valence angle = 90° 44'; excited state, r' 0 = 1.48 Å, valence angle = 123° 0'. The parameters associated with rotation about the a inertial axis increase rapidly with increase in v' 2 . The spectrum shows doublet splittings of up to 41 cm -1 , and the excited state furnishes the first example of a doublet state of an asymmetric top molecule which shows substantial departures from Hund’s case ( b ).

ULTRAVIOLET SPECTRA OF LiH AND LiD

1957 ◽  
Vol 35 (10) ◽  
pp. 1204-1214 ◽  
Author(s):  
R. Velasco
Keyword(s):  
Excited State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
High Dispersion ◽  
Dissociation Energies ◽  
Near Ultraviolet ◽  
Path Lengths ◽  
Vibrational Constants ◽  
Π State

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.

Etude à basse température dans l'infrarouge proche du dimère (NO)2

1984 ◽  
Vol 62 (4) ◽  
pp. 322-329 ◽  
Author(s):  
V. Menoux ◽  
R. Le Doucen ◽  
C. Haeusler ◽  
J. C. Deroche
Keyword(s):  
Excited State ◽  
Gas Phase ◽  
Ground State ◽  
Near Infrared ◽  
Heat Of Formation ◽  
Wave Number ◽  
Vibrational Modes ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Absorption Intensity

The spectrum of the dimer (NO)2 in the gas phase has been studied in the near infrared at temperatures between 118 and 138 K. More specifically, the measure of absorption intensity of the ν4 and ν1 + ν4 bands has yielded the heat of formation of the dimer, −2.25 kcal/mol at 128 K, and revealed the influence of the low vibrational modes on this measure. The observation of the ν4 – ν6, difference band has yielded the wave number value of the ν6, fundamental band, forbidden in the infrared. The rotational constants of the vibrationally excited state were found to be larger than the ground state rotational constants, this result being very unusual.

Rotational Spectrum of 2,3-Benzofuran

2003 ◽  
Vol 68 (9) ◽  
pp. 1572-1578 ◽  
Author(s):  
B. Michela Giuliano ◽  
Walther Caminati
Keyword(s):  
Excited State ◽  
Ground State ◽  
Rotational Spectrum ◽  
Frequency Range ◽  
Supersonic Expansion ◽  
Rotational Constants ◽  
Millimetre Wave ◽  
Rotational Spectra ◽  
Wave Absorption ◽  
Free Jet

The rotational spectra of the ground state and of one vibrational satellite of 2,3-benzofuran have been measured by millimetre-wave absorption free jet spectroscopy in the frequency range 60-78 GHz. The value of the inertial defect (-0.072 uÅ2) shows the molecule to be planar. The shifts of the rotational constants in going from the ground to the excited state indicate that the observed vibrational satellite does not belong to the two lowest energy motions, the butterfly and 1,3-ring-twisting, which undergo relaxation upon the supersonic expansion.

ENERGY LEVELS OF A POLARON IN A FINITE PARABOLIC QUANTUM WELL

2001 ◽  
Vol 15 (05) ◽  
pp. 527-535 ◽  
Author(s):  
FENG-QI ZHAO ◽  
XI XIA LIANG ◽  
SHILIANG BAN
Keyword(s):  
Excited State ◽  
Variational Method ◽  
Quantum Well ◽  
Ground State ◽  
Transition Energy ◽  
Energy Levels ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Hole Energy ◽  
First Excited State

The effects of the electron–phonon interaction on the electron (or hole) energy levels in parabolic quantum well (PQW) structures are studied. The ground state, the first excited state and the transition energy of the electron (or hole) in the GaAs/Al 0.3 Ga 0.7 As parabolic quantum well are calculated by using a modified Lee–Low–Pines Variational method. The numerical results are given and discussed. A comparison between the theoretical and experimental results is made.

Vibration-rotation bands of monodeuteroacetylene and the molecular dimensions

1956 ◽  
Vol 234 (1198) ◽  
pp. 306-317 ◽  
Keyword(s):  
High Resolution ◽  
Ground State ◽  
Fermi Resonance ◽  
Rotational Constants ◽  
Bond Lengths ◽  
Vibrational Levels ◽  
Vibration Rotation ◽  
Molecular Dimensions

Some vibration-rotation bands of monodeuteroacetylene have been measured with high resolution. Values have been derived for the coefficients α i relating the rotational constants in different vibrational levels, as follows: α 2 = + 0⋅00439, α 3 = + 0⋅00638, α 4 = — 0⋅0032 2 , α 5 = — 0⋅0011. Using the value B 00000 = 0⋅9910 5 cm -1 , also determined from many bands, a new value, B e = 0⋅9948, has been obtained leading to new estimates for the bond lengths r e CH = 1⋅058 Å, and r e C≡C = 1⋅205 0 . The l -doubling coefficient has been determined in two states, namely, q 00010 = 0⋅0056 and q 00003 = 0⋅0072. In the ground state the results are in accordance with a centrifugal stretching coefficient D = 0⋅7 x 10 -6 , but in some higher levels a markedly different value is derived, which may, however, arise through the effects of Fermi resonance.

Rotational Structure in the (2,0) Band of the C2 Δ3/2–X2 Π1/2 Subsystem of SbO

1974 ◽  
Vol 52 (7) ◽  
pp. 592-598 ◽  
Author(s):  
S. B. Rai ◽  
B. Rai ◽  
D. K. Rai
Keyword(s):  
Excited State ◽  
Ground State ◽  
Rotational Structure ◽  
Third Order ◽  
Rotational Constants ◽  
The Third ◽  
Concave Grating ◽  
Combining States

The rotational structure in (2,0) band of C2Δ3/2–X2Π1/2 subsystem of SbO molecule has been photographed in the third order of a 35 ft concave grating spectrograph, and the rotational constants of the two combining states have been determined. It is found that the new rotational constants for the ground state are in agreement with those reported by Rai et al., but the constants for the excited state differ appreciably from those reported earlier by Rao and Rao. A small λ-type doubling (≈4.0 × 10−6 cm−1) is observed in the excited state. The isotopic lines due to 123SbO have also been observed.

Group theoretical analysis of nitrogen-vacancy center’s energy levels and selection rules

2011 ◽  
Vol 1282 ◽  
Author(s):  
J. R. Maze ◽  
A. Gali ◽  
E. Togan ◽  
Y. Chu ◽  
A. Trifonov ◽  
...  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Energy Levels ◽  
Vacancy Defect ◽  
Nitrogen Vacancy ◽  
Spin Interaction ◽  
State Structure ◽  
Spin Properties ◽  
State Configuration ◽  
Group Theoretical Analysis

ABSTRACTWe use a group theoretical approach to model the nitrogen-vacancy defect in diamond. In our analysis we clarify several properties of this defect that have been source of controversy such as the ordering of the singlets and the mechanism that leads to spin mixing in the excited state of this defect. In particular, we demonstrate that the ordering of the ground state configuration (e2) is {3A2, 1E, 1A1} and that the spin-spin interaction causes the mixing in the excited state. In addition, we analyze the angular momentum and spin properties of the excited state structure that enables a spin photon entanglement scheme that has been recently demonstrate experimentally. Our description is general and it can be easily applied to other defects in solid-state systems.

Rotational band contours in electronic spectra of large asymmetric top molecules: the 2750 Å system of phenol

1968 ◽  
Vol 307 (1488) ◽  
pp. 97-110 ◽  
Keyword(s):  
Excited State ◽  
Rotational Band ◽  
Point Group ◽  
Resolving Power ◽  
Hydroxyl Group ◽  
Rotational Constants ◽  
Selection Rules ◽  
Electronically Excited ◽  
Band Contour ◽  
Characteristic Features

The rotational band contour of the 0–0 band of phenol at 2750 Å has been recorded experimentally with a resolving power of 300000. The contour contains many characteristic features of which a series dependent on K a has been used to obtain trial sets of rotational constants A', B' and C' in the electronically excited state. The excited state was assumed to be planar. These data together with rotational selection rules were used in an asymmetric rotor band contour computer program and the rotational constants varied until the com­puted contour matched the observed. The contours were matched only by using type B selection rules. The electronic assignment is therefore 1 B 2 – 1 A 1 (using the C 2 v point group) and the excited state rotational constants are : A ' = 0·1773 ± 0·0002 cm -1 ; B ' = 0·08751 ± 0·00006 cm -1 ; C ' = 0·05859 ± 0·00001 cm -1 . These constants reflect an appreciable interaction of the hydroxyl group with the ring in the excited state whereas microwave data have shown very little interaction in the ground state. In particular, there is a slight overall contraction of the molecule along the long in-plane inertial axis from the ground to the excited state in contrast to an expected expansion if there were no hydroxyl group interaction. The origin of the 2750 Å 0–0 band is at 36 348·7 ± 0·2 cm -1 .

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