Spin molecular

The energy 7i(S) of a given configuration of N spins is made up of two parts (1) a contribution that arises solely from the inter-spin molecular forces (= Hst s), and (2) a contribution that is due to the interaction between the spins and any external magnetic fields (= Since 5, is effectively the magnetic moment... 

From experimental results, the variation of film thickness with rolling velocity is continuous, which validates a continuum mechanism, to some extent in TFL. Because TFL is described as a state in which the film thickness is at the molecular scale of the lubricants, i.e., of nanometre size, common lubricants may exhibit microstructure in thin films. A possible way to use continuum theory is to consider the effect of a spinning molecular confined by the solid-liquid interface. The micropolar theory will account for this behavior. 

Since these hypothetical electrons are noninteracting v /,. can be written exactly (for a closed-shell system) as a single Slater determinant of occupied spin molecular orbitals (Section 5.2.3.1). For a real system, the electrons interact and using a single determinant causes errors due to neglect of electron correlation (Section 5.4), the root of most of our troubles in wavefunction methods. Thus for a four-electron system... 

In this section we report the first study of the micro-SQUID response of a low-spin molecular system, V15, to electromagnetic radiation. The advantages of our micro-SQUID technique in respect to pulsed electron paramagnetic resonance (EPR) techniques consist in the possibility to perform time-resolved experiments (below 1 ns) [59] on submicrometer sizes samples (about 1000 spins) [22] at low temperature (below 100 mK). Our first results on Vi5 open the way for time-resolved observations of quantum superposition of spin-up and spin-down states in SMMs. Other results obtained in similar systems but with large spins concern for example EPR measurements [10], resonant photon-assisted tunneling in a Feg SMM [60]. 

Proceedings of the Symposium on Ferromagnetic find High Spin Molecular Based Materials, Mol. Cryst. Liq. Cryst. 176 (1989). 

Miller JS, Dougherty DA (eds) (1989) Proceedings of the Symposium of Ferromagnetic and high spin molecular based materials. Mol Cryst Liq Cryst 176 1... 

As we have seen previously (Chapter 5), the eigenfunction for a polyelec-tronic atom is antisymmetric with respect to the exchange of the coordinates of any two electrons, and can be expressed as a Slater determinant whose elements are the various occupied spin-orbitals (or a linear combination of Slater determinants, in the case of open-shell atoms). The same appfies to polyelectronic molecules, the atomic orbitals being replaced by the various occupied molecular orbitals associated with the a and /3 spin-functions spin molecular orbitals. Thus, for the molecules H2O, NH3 or CH4 having five doubly occupied m.o.s (one core s orbital and four valence m.o.s), we have... 

For the development below, we will assume a closed-shell situation, with all electrons paired in molecular orbitals. In such a case OfSj = 1. In very many cases, however, an unrestricted Hartree-Fock (UHF) scheme is utilized for ground state properties. This theory is reasonably accurate for those cases in which each open-shell orbital has an electron of the same spin, i.e., the case that an open-shell has maximum multiplicity. In the UHF scheme Eq. [4] does not hold. Two Fock equations result, one for a and one for 3 spin molecular orbitals. In cases in which excited state properties are required, Eq. [4] is forced to hold in order to yield spectroscopic states, of known multiplicity. OfSJ can then become quite complex, and affects the form of the Fock operators that follow. ... 

When we studied the radio-frequency spectrum of D2 we hit another surprise [5]. The separation of the spectral lines in D2 were greater than in H2 even though the nuclear spin-spin interaction and the nuclear spin molecular rotation interaction should be much less. We found a similar anomaly for HD. We finally interpreted this as due the deuterium nucleus having a quadrupole moment (being ellipsoidal in shape) which gave rise to a spin dependent electrical interaction. The existence of the quadrupole moment, in turn, implied the existence of a new elementary particle force called a tensor force. In this way, magnetic resonance made a fundamental contribution to particle physics. 

In laser pyrolysis, a precursor in the gaseous form is mixed with an inert gas and heated with CO2 infrared laser (continuous or pulsed), whose energy is either absorbed by the precursor or by an inert photosensitizer such as SFs. Swihart [84], Ledoux et al. [116,117], and Ehbrecht and Huisken [118] prepared Si nanoparticles by laser pyrolysis of silane. By using a fast-spinning molecular beam chopper, Si nanoparticles in the size range of 2.5-8 nm were deposited on quartz substrates to study quantum confinement effects [116]. Li et al. [119] improved the stability of the Si nanoparticles ( 5 nm) by surface functionalization and obtained persistent bright visible photoluminescence. Hofmeister et al. [120] have studied lattice contraction in nanosized Si particles produced by laser pyrolysis. The method has been used to synthesize metal nanoparticles as well (see Table 2.1). Zhao et al. [121] obtained Co nanoparticles by laser pyrolysis of Co2(CO)s vapor at a relatively low temperature of 44° C. Ethylene was used as a photosensitizer for CO2 laser emission. Nanoparticles... 

This contribution reviews the basic tools which are currently employed for interpreting ESR and NMR observables in condensed phases, with an emphasis on stochastic modeling as key for the prediction of continuous-wave ESR (cw-ESR) lineshapes and NMR relaxation times of proteins. Section 12.2 is therefore devoted to the definition of reduced (effective) magnetic Hamiltonians and the stochastic (Liouville) approach to spin/molecular dynamics in order to clarify the basic stochastic approach to cw-ESR observables. Section 12.3 provides a short overview of rotational stochastic models for the evaluation of relaxation NMR data in biomolecules. Conclusions are briefly summarized in Section 12.4. 

ROSSNER et al. [10.27d] measured the very small hfs splitting (<100 kHz) of a rovibronic level (v" = 0, J" = 28) in the X ground state of the Na2 molecule. This splitting is much smaller than the natural linewidth of the optical transitions. The quadrupole coupling constant was determined to e q Q = 463.7 0.9 kHz and the nuclear spin-molecular rotation interaction constant came out to be a = 0.17 0.03 kHz. 

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