Unrestricted Hartree-Fock Investigation of the Electron Distribution on the Heme System in Azidohemoglobin-$^{57m}$Fe and $^{14}$N Hyperfine Interactions.

We have a program of investigations in progress on the electronic structure of azidohemoglobin by the first-principles Unrestricted Hartree-Fock procedure to understand the substantial amount of magnetic (g-tensor), magnetic hyperfine, and nuclear quadrupole interaction, data available [1] from electron paramagnetic resonance, Mosbauer and electron-nuclear double resonance measurements. Earlier semi-empirical Self-Consistent Charge Extended Huckel investigations have provided semiquantitative results [2] with different degrees of agreement for the available properties and suggested the need for more accurate and quantitative investigations. Results of our investigations will be presented for the $^{57m}$Fe and $^{14}$N nuclear quadrupole and magnetic hyperfine interaction properties and compared with experimental data. *Also UCF Orlando [1] See Refs. 2-4 listed in Ref.[2]. [2] Santosh K. Mishra, J.N. Roy, K.C. Mishra and T.P. Das, Theo. Chim. Acta 75, 195(1989).