THE NEAR ULTRAVIOLET BANDS OF N2+ AND THE DISSOCIATION ENERGIES OF THE N2+ AND N2 MOLECULES

1952 ◽  
Vol 30 (4) ◽  
pp. 302-313 ◽  
Author(s):  
A. E. Douglas
Keyword(s):  
Quantum Number ◽  
Dissociation Energy ◽  
Ground State ◽  
Strong Support ◽  
Dissociation Limit ◽  
Vibrational Quantum Number ◽  
Ultraviolet Emission ◽  
Dissociation Energies ◽  
Near Ultraviolet

The ultraviolet emission bands of N2+ have been photographed using a six meter grating, and a number of new bands of high vibrational quantum number have been found. It has been possible to show that the [Formula: see text] state dissociates at a limit 70,358 cm.−1 above the ground state. It is shown that these results give strong support to the value 9.75 electron volts for the dissociation energy of nitrogen, but the lower value of 7.37 electron volts cannot be eliminated with certainty. The peculiar manner in which the B2Σ state converges to its dissociation limit is interpreted as being caused by an interaction between the [Formula: see text] and the [Formula: see text] states.

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.

Two New Band Systems in the Near Ultraviolet Spectrum of N2

1975 ◽  
Vol 53 (19) ◽  
pp. 2198-2209 ◽  
Author(s):  
P. K. Carroll ◽  
K. V. Subbaram
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Rydberg State ◽  
Molecular Nitrogen ◽  
Ultraviolet Spectrum ◽  
Dissociation Limit ◽  
Ultraviolet Emission ◽  
Weak Band ◽  
Near Ultraviolet ◽  
Unusual Type

Two new weak band systems have been identified under high resolution in the near ultraviolet emission spectrum of molecular nitrogen. They are found to arise from a transition from a hitherto unknown 1Πg state, which it is proposed to call k, to the a′ 1Σu− and w1Δu states. The upper state is interpreted as the 1ΠgRydberg state of configuration … (1πu)4 (3σg) 3dπg. Straightforward treatment of the data by conventional methods gives B0d = 1.906 cm−1, B1d = 1.824 cm−1, T0 = 113 630.87 cm−1, and ΔG1/2 = 2305.92 cm−1. Only the d levels, i.e., the levels corresponding to the 1Πg− component, are observed and the absence of the c levels is attributed to an unusual type of predissociation involving the predicted stable 1Σg+ state which goes to the dissociation limit 2D + 2D (14.522 eV) and the 3Σg− state which arises at the limit 4S + 2P (13.332 eV). A new level at 117 661.11 cm−1 with a Bd value of 1.695 cm−1 is identified as v = 2 of the y1Πg state. A strong homogeneous interaction is found to be occurring between the new k1Πg state and the y1Πg state. A deperturbation calculation is carried out and yields the following deperturbed constants: k1Πg: Be = 1.959 cm−1; αe = 0.031 cm−1; re = 1.109 Å; T0 = 113 723.58 cm−1; ΔG1/2 = 2182.32 cm−1, y1Πg: Be = 1.739 cm−1; αe = 0.017 cm−1; re = 1.177 Å; Te = 114 314.36 cm−1; ωe = 1906.43 cm−1; αexe = 37.51 cm−1.

scholarly journals Determination and Study the Energy Characteristics of Vibrational-Rotational Levels and Spectral Lines of GaF, GaCl, GaBr and GaI for Ground State

2015 ◽  
Vol 50 ◽  
pp. 96-112
Author(s):  
Adil Nameh Ayaash
Keyword(s):  
Quantum Number ◽  
Computer Model ◽  
Ground State ◽  
Theoretical Study ◽  
Rotational Quantum Number ◽  
Spectral Lines ◽  
Vibrational Quantum Number ◽  
Energy Characteristics ◽  
Number Increase ◽  
The Relationship

A theoretical study of four gallium monohalides molecules (GaF, GaCl, GaBr and GaI) of ground state 1∑+ by using computer model is presented to study the energy characteristics of vibrational-rotational levels as a function of the vibrational and rotational quantum number , respectively. The calculations has been performed to examine the vibrational-rotational characteristics of some gallium halides molecules. These calculations appeared that all energies (Gv, Ev,J, and Fv,J) increase with increasing vibrational and rotational quantum number and by increasing the vibrational quantum number, and by increasing the vibrational quantum number, the vibrational constant will decrease. Also theoretical study of spectra of these molecules for ground state 1∑+ has been carried out. The values of spectral lines R(J) and P(J) were calculated and the relationship between the spectral lines and the rotational quantum number was established. The results appeared the spectra line values R(J) increases when the values of rotational quantum number decrease but the spectra line values P(J) decrease when the values of rotational quantum number increase, also the spectra line values P(J) decrease when the values of (m) increase, while the values of R(J) increase at first, then decrease showing Fortrar parabola.

FORBIDDEN TRANSITIONS IN DIATOMIC MOLECULES: II. THE ABSORPTION BANDS OF THE OXYGEN MOLECULE

1952 ◽  
Vol 30 (3) ◽  
pp. 185-210 ◽  
Author(s):  
G. Herzberg
Keyword(s):  
Dissociation Energy ◽  
Band System ◽  
Opposite Sign ◽  
Dissociation Limit ◽  
Spin Orbit Coupling ◽  
Absorption Bands ◽  
Near Ultraviolet ◽  
Triplet Splitting ◽  
Forbidden Transition ◽  
Low Dispersion

The forbidden [Formula: see text] absorption bands of O2 in the near ultraviolet have been obtained under high resolution with absorbing paths up to 800 m. A detailed fine structure analysis has been carried out. It confirms the identification of the band system as a [Formula: see text] transition. Precise values of the rotational constants Bν and Dν as well as of the vibrational quanta [Formula: see text] in the upper state have been derived. Each of the "lines" of the Q branches observed under low dispersion is resolved into six components whose spacing yields the triplet splitting in the upper state. This splitting is more than twice as large as in the [Formula: see text] ground state and is of opposite sign. The splitting constants λ and γ have been determined and their variation with the vibrational quantum number observed. In addition to the Q-form branches weak O- and S-form branches have been found in agreement with the prediction of Present which is based on the assumption that spin–orbit coupling is the main cause for the occurrence of this forbidden transition. However, the relative intensities of the different branches deviate strongly from Present's prediction. The dissociation limit obtained from the convergence limit of the bands (without extrapolation) is at 41219 ± 40 cm.−1 This value is higher by about 220 cm.−1 than the value of the dissociation energy of O2 derived from the Schumann–Runge bands. It is possible that the limit of the Schumann–Runge bands, which is based on a short extrapolation, and therefore the value of the dissociation energy of O2 has to be slightly revised. The electron configurations and dissociation products of the various electronic states of O2 are briefly discussed.

The X40x10 Halogen Bonding Benchmark Revisited: Surprising Importance of (n-1)d Subvalence Correlation

2017 ◽  
Author(s):  
Manoj Kumar Kesharwani ◽  
Nitai Sylvetsky ◽  
Debashree Manna ◽  
Jan M.L. Martin
Keyword(s):  
Dissociation Energy ◽  
Noncovalent Interactions ◽  
Halogen Bonding ◽  
Coupled Cluster ◽  
Dissociation Energies ◽  
Iodine Species ◽  
Explicitly Correlated ◽  
High Level ◽  
Cluster Methods ◽  
Small Separation

<p>We have re-evaluated the X40x10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)–MP2 “high-level corrections” (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n-1)d subvalence correlation increases dissociation energies, and turns out to be more important for noncovalent interactions than is generally realized. As in previous studies, we find that the most efficient way to obtain HLCs is to combine (T) from conventional CCSD(T) calculations with explicitly correlated CCSD-F12–MP2-F12 differences.</p>

Notizen:Phosphorescence Decay in Thallium-Doped Ammonium Chloride

1978 ◽  
Vol 33 (10) ◽  
pp. 1241-1242 ◽  
Author(s):  
S. Chaudhari ◽  
T. R. Joshi ◽  
R. V. Joshi
Keyword(s):  
Aqueous Solution ◽  
Ammonium Chloride ◽  
Mechanical Treatment ◽  
Room Temperature ◽  
Host Lattice ◽  
Luminescence Decay ◽  
Decay Rates ◽  
Negative Ion ◽  
Ultraviolet Emission ◽  
Near Ultraviolet

Abstract The phosphorescence decay rates of thallium-doped ammonium chloride (NH4Cl:Tl) phosphors, prepared by crystallization from aqueous solution, have been studied at room temperature for near-ultraviolet emission. The effects of impurity concentration as well as thermal and/or mechanical treatment on the decay rates have been examined. Phosphorescence centres consisting of a Tl+ion and a nearby negative ion vacancy are suggested to be responsible for the observed luminescence decay. The changes in the decay characteristics after pretreatments are explained on the basis of the location of the centres in normal and distorted regions of the host lattice.

scholarly journals The thermochemistry of carbon: valence states, heats of sublimation and energies of linkage

1946 ◽  
Vol 187 (1010) ◽  
pp. 337-357 ◽  
Keyword(s):  
Ground State ◽  
Electronic Configuration ◽  
Dissociation Energies ◽  
True Value ◽  
Valence States ◽  
Chemical Combination ◽  
The Right ◽  
Right Order ◽  
Unambiguous Assignment ◽  
Apparent Conflict

The controversy which exists at the present time between the figures 125 and 170 kcal./g.- atom for the latent heat of sublimation of carbon into monatomic vapour in the ground state originates largely from the neglect to take into consideration the energy required to raise the carbon atoms from the ground ( 3 P ) state to the lowest tetravalent ( 5 S ) electronic configuration corresponding to that in which it is normally found in chemical combination. Consideration of the energies of removal of a hydrogen atom from the methane and ethane molecules and of the energies of reorganization of the resulting radicals leads to the figure 190 ± about 10 kcal. for L 2 , the heat of sublimation into free atoms in the 5 S state. This in turn leads to a satisfactory and unambiguous assignment of values to bond energies (as distinct from dissociation energies) which can now be expressed with an uncertainty of not more than a few kcal. In the light of the valency distinction there remains no sound evidence to maintain the higher value put forward for L 1 and 125 kcal. is unquestionably of the right order. There are strong indications that an earlier estimate of 100 kcal. for the energy level of the 5 S state above the 3 P (ground) state is about 50 % in excess of the true value. The necessity for establishing this branch of thermochemistry on a sound theoretical and experimental footing has long been a very obvious need. The scheme here suggested reconciles points hitherto in apparent conflict, and brings virtually all established experimental knowledge into alignment.

The C—Br bond dissociation energy in halogenated bromomethanes

1951 ◽  
Vol 209 (1096) ◽  
pp. 110-131 ◽  
Keyword(s):  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Methyl Bromide ◽  
Frequency Factor ◽  
Unimolecular Dissociation ◽  
Bond Dissociation Energies ◽  
Kcal Mole ◽  
Fast Reaction ◽  
Bond Dissociation ◽  
Dissociation Energies

The pyrolyses of methyl bromide and of the halogenated bromomethanes, CH 2 CI. Br, CH 2 Br 2 , CHCl 2 .Br, CHBr 3 , CF 3 Br, CCI 3 . Br and CBr 4 , have been investigated by the ‘toluene-carrier' technique. It has been shown that all these decompositions were initiated by the unimolecular process R Br → R + Br. (1) Since all these decompositions were carried out in the presence of an excess of toluene, the bromine atoms produced in process (1) were readily removed by the fast reaction C 6 H 5 .CH 3 + Br → C 6 H 5 . CH 2 • + HBr. Hence, the rate of the unimolecular process (1) has been measured by the rate of formation of HBr. The C—Br bond dissociation energies were assumed to be equal to the activation energies of the relevant unimolecular dissociation processes. These were calculated by using the expression k ═ 2 x 10 13 exp (- D/RT ). The reason for choosing this particular value of 2 x 10 13 sec. -1 for the frequency factor of these reactions is discussed. The values obtained for the C—Br bond dissociation energies in the investigated bromomethanes are: D (C—Br) D (C—Br) compound (kcal./mole) compound (kcal./mole) CH 3 Br (67.5) CHBr 3 55.5 CH 2 CIBr 61.0 CF 3 Br 64.5 CH 2 Br 2 62.5 CCI 3 Br 49.0 CHCl 2 Br 53.5 CBr 4 49.0 The possible factors responsible for the variation of the C—Br bond dissociation energy in these compounds have been pointed out.

scholarly journals Rotation Effect in Morse Potential For K2 Molecule

2011 ◽  
Vol 8 (4) ◽  
pp. 968-971
Author(s):  
Baghdad Science Journal
Keyword(s):  
Quantum Number ◽  
Dissociation Energy ◽  
Effective Potential ◽  
Morse Potential ◽  
Rotational Quantum Number ◽  
Electronic States ◽  
Rotation Effect ◽  
Potential Curves

The rotation effect upon Morse potential had been studied and the values of the effective potential in potential curves had been calculated for electronic states (X2?+g , B ?u ) K2 molecule. The calculation had been computed for rotational quantum number (J = 5). Also, drawing potential curves for these systems had been done using Herzberg and Gaydon equations. It was found that the values of the dissociation energy which resulting from using Herzberg equation greater than that of Gaydon equation. Besides, it was found that the rotation effect for (X and B) electronic states in Morse potential is very small and in this case may negligible.

Sign in / Sign up

Export Citation Format

Share Document