Properties and Spectra

Finally, the presence of the two rotamers in all phases of N2F4 could be proved by (1) reinvestigation of the electron diffraction and (2) detailed spectroscopic studies  

Bond lengths r (in A), bond angles and dihedral angle (in °), mean amplitudes of vibration u (in A), trans gauche ratio (in %), and energy difference AE(trans-gauche) (in cal/mol). 

See Fig. 8, p. 307. - Weighted averages for trans and gauche form. - Amplitudes for the remaining nonbonded F---F and N---F pairs are also given [16 to 18]. 

According to a qualitative discussion on N2H4 and N2P4 based on the so-called molecular orbital-valence bond theory, the N2P4 molecule tends to adopt the trans form rather than the gauche form (of N2H4) [39]. 

An ab initio MO calculation of the total energy as a function of 0 from 0° to 360° (GTO basis for (N/P) of (7s3p/7s3p) contracted to [2s1 p/2s1 p], experimental bond lengths and bond angles [11]) predicted two stable forms at 0 = 64° or 296° and 0 = 180°, with the trans form being more 

The isomer trans-N2 2 has been detected and identified experimentally, specifically through its IR and UV spectra in the gas phase. The existence of the cis isomer has been sometimes suggested, but it could not be unambiguously identified. The cis isomer is regarded to be a transient intermediate in many reactions. 

The Walsh rules predict C2V symmetry for the amide ion just as for the isoelectronic water molecule [1]. Experimental results confirm the theoretical predictions  

015(50) 109(18)° quasi-elastic neutron scattering by solid KNH2 [4] 

Similar structural data for the amide ion were derived from the IR bands of LiNH2 [9] and from the NMR spectrum of solid KNH2 taken at 90 K [10]. Calculations based on crystal parameters were done for NaNH2 (see Natrium Erg.-Bd. 3, 1966, p. 921), Ca(NH2)2, and Sr(NH2)2 [11]- 

The ion in the electronic ground state with the electron configuration (la ) (2ai) (1b2) (3ai) (1bi) has Ai symmetry. The highest occupied molecular orbital is a nonbonding, lone-pair orbital of nitrogen [1, 2, 12] see also p. 170. 

The energy required to remove an electron from NH2 has been determined in several gas-phase photodetachment studies. The experimentally measured, vertical photodetachment energy of NHJ is identical with the adiabatic electron affinity of the NH2 radical, because both species have similar structures and are in their electronic ground state [13, 14]. Numerical values are given in the section on the electron affinity of NH2 on p. 176. 

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Quantum Systems in Chemistry and Physics is a broad area of science in which scientists of different extractions and aims jointly place special emphasis on quantum theory. Several topics were presented in the sessions of the symposia, namely 1 Density matrices and density functionals 2 Electron correlation effects (many-body methods and configuration interactions) 3 Relativistic formulations 4 Valence theory (chemical bonds and bond breaking) 5 Nuclear motion (vibronic effects and flexible molecules) 6 Response theory (properties and spectra atoms and molecules in strong electric and magnetic fields) 7 Condensed matter (crystals, clusters, surfaces and interfaces) 8 Reactive collisions and chemical reactions, and 9 Computational chemistry and physics. 

Response Theory-Properties and Spectra Atoms and Molecules in Strong Fields... 

Nuclear motion, vibronic effects, and flexible molecules (Chair J. Maruani) Response theory—Properties and spectra Atoms and molecules in strong electric and magnetic fields (Chair J. Gerratt)... 

Compound Property Predictors (for physical chemical properties and spectra) Advanced Chemistry Development (ACD Labs) 60 http //www.acdlabs.com... 

Next, we study systematically the behavior of the compound toward certain reagents. This behavior, taken with the elemental analysis, solubility properties, and spectra, generally permits us to characterize the compound, that is, to decide what family the unknown belongs to. We might find, for example, that the compound IS an alkane, or that it is an alkenc, or an aldehyde, or an ester. 

The aldehyde XXXIII was converted by phosgene into the vinylogous imidoyl chloride XXXIV which was condensed with 4a-methylhexahy-drocarbazole XXXV in the presence of base to give the product XXXVI isolated and characterized as its yellow crystalline perchlorate. A series of related compounds was also prepared am I the properties and spectra of the whole group of substances gives strengtJ i to the assigned structures. 

Molecular Properties and Spectra 3.4.5.1 Point Group. Isomerism... 

Molecular Properties and Spectra 3.14.3.1 Electronic Structure Ground State... 

The synthesis of dinitrogen tetrafluoride in 1958 was the beginning of a period where numerous previously unknown substances were synthesized. The preparations, properties, and reactions of N2F4 have been intensively studied. The most remarkable property is its reversible dissociation into NF2 radicals, N2F4 2NF2, which explains many of the chemical properties of N2F4. Due to the relative stability of the NF2 radical, its molecular properties and spectra are well investigated. 

Molecular Properties and Spectra 4.1.4.6.1 Electronic Structure. Bonding... 

Molecular Properties and Spectra Electron Configurations. Ionization Energies... 

In the following sections on molecular properties and spectra of NH, only a few relevant calculations will be occasionally quoted in order to supplement the experimental results or in cases where experimental results either are not available or are disagreeing or uncertain. Otherwise, the reader is referred to the bibliographies. 

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