V.R. Marathe

On the calculation of average magnetic susceptibility for anistropic paramagnetic systems

Abstract It is shown that the expression x = 1 3 x|+ 2 3 x⊥ gives fairly incorrect results when used in the saturation region for highly paramagnetic anistropic systems. Explicit expressions for the average magnetic susceptibility in the saturation region are suggested, which besides being extremely accurate, involve computation of the susceptibility only in 3 or 4 fixed directions.

Magnetic properties and electronic structure of manganese(III) porphyrins

Abstract The average magnetic susceptibility (1.2-100 K) and magnetisation (100–15000 Oe at 4.2 K) of two perchlorato manganese(III) porphyrins establish them to be high-spin, in contrast to the “anomalous” behaviour of analogous iron(III) porphyrins. An explanation of the origin of the zero-field splitting in high-spin manganese(III) porphyrins is presented.

Magnetic behaviour of spin-mixed iron(III) porphyrins

Detailed average magnetic susceptibility (295-4.2 K) and average magnetisation (20-2 K, 50-10 kOe) are reported for two novel spin-mixed iron(III) porphyrins, namely Fe(TPP)ClO4 and Fe(OEP)ClO4. The results confirm an S = 3/2 ground state substantially spin-mixed with a low-lying S = 5/2 state, but do not agree in detail with the crystal-field model of Maltempo.

Low-temperature magnetisation study on manganese(III) porphyrins

Abstract Average magnetisation between 2 and 20 K and 10 and 50 kOe of two typical high-spin manganese(III) porphyrins, namely TPPMnCI and TPPMnCl(py), is reported for the first time. The results have been analysed in terms of spin hamiltonian formalism including both the crystal field and magnetic exchange.

Potential energy curves of low-lying electronics states of CO2+

Abstract This paper presents a brief overview of the prevailing ambiguity surrounding the quantal description of low-lying electronic states of CO 2+ . New ab initio, all-electron molecular-orbital calculations on the 1 Σ + , 3 Π and 3 Σ − states have been carried out using large basis sets and correlation procedures; the results are considered in the light of recent experimental data obtained from ion translational energy spectrometry involving CO 2+ ions.

Zero-field splitting in hemin

Abstract A spin-hamiltonian formalism which includes magnetic-field-induced mixing and fourth-order crystal-field terms, is successfully employed to explain the low-temperature magnetic-susceptibility behaviour of hemin.

Paramagnetic anisotropy and zero-field splitting in chloro bis (diethyldithiocarbamato) iron (III)

Results of measurements of paramagnetic anisotropy in the 80–300°K temperature range on single crystals of S = 3/2 chloro bis (diethyldithiocarbamato) iron (III) are described. The values of the axial and rhombic zero-field splitting parameters are deduced: D = 1.73 cm−1 and E = 1.19 cm−1.

Zero-field splitting and the low-temperature magnetic susceptibility of tris (pyrrolidine-I-carbodithioato) iron (III)

Abstract It is demonstrated that the existing discrepancy in the interpretation of low-temperature magnetic-susceptibility data on high-spin tris (pyrrolidine-I-carbodithioato) iron (III) disappears when high-order magnetic-field effects and fourth-order ligand-field terms are considered.

The dynamics of the formation of S2+ from CS2 by electron impact

Abstract The dynamics of the formation of S2+ from CS2 by electron impact has been investigated by ion kinetic energy spectrometry and ab initio quantum chemical calculations on the CS2+ and CS22+ ions. The results show that S2+ is formed through a sequential process in which some of the linear CS2+ or CS22+ ions formed initially undergo a geometric change to a bent shape before dissociating to give S2+ ions.

Temperature dependence of the proton magnetic resonance spectra of halogeno-bis(N, N′-diethyldithicarbamato)iron (III)☆

The paper reports proton magnetic resonance studies between +60°C to −60°C on a series of intermediate spin (S= 32) halogeno-bis(diethyldithiocarbamato)iron (III). The pseudocontact shift (PCS) at various temperatures has been estimated from the experimentally measured paramagnetic anisotropies. The results show the marked effect of the T−2 term in the iodo derivative and this is rationalized in terms of the large ground state zero-field splitting of the ferric ion. The temperature variation of the contract shift is also discussed in terms of the electronic structure of the ferric ion. The temperature variation study has revealed a conformational change in these molecules, which has been ascribed to a hindered S2CN rotation. The thermodynamic parameters describing this kinetic process have been calculated.