Analytic Potential Energy Function for Doubly Charged Ions HBe^(2+), HB^(2+), and HF^(2+)

It is well known that the potential curve of ground state for almost all neutral diatomic molecules has only one minimum.However,the doubly charged diatomic ions may have both potential minimum and maximum or singly repulsive branch.In order to describe the potential of this kind of diatomic ions,two of the authors Zhu and Wang have proposed a new analytical potential function with four parameters ai(i=l,...,4),andρ=R-R_(min) for those with both minimum and maximum,andρ=R for those with singly repulsive branch.The present work has derived this new potential function for HBe^(2+)with R_(min)=0.182 nm,R_(max)=0.335 nm andΔE=E_(max)-E_(min)=0.84 eV,and for HBe2+with R_(min)=0.147 nm,R_(max)=0.185 nm andΔE=E_(max)-E_(min)=0.062 eV.It is found that the potential for HF^(2+)is one with singly repulsive branch.The dissociation limits,parameters ai(i=1,...,4),force constants and spectroscopic data of these ions all are given out.

Restudy of Grüneisen Parameter of Iron in the Pressure Range of 90-160 Gpa

The Hugoniot equation-of-state(EOS)of porous iron with an average initial density of 6.904g/cm^(3) has been measured in the pressure range from 90 to 160GPa,and a good straight fitting D=2.997+1.603u has accordingly been obtained,where D is the shock wave velocity and u the particle velocity,both in units of km/s.Combining this with the Hugoniot EOS of non-porous iron,the Grüneisen EOS and the Rankine-Hugoniot energy conservation relation,and taking the possible solid-liquid transition correction,we have calculated the Grüneisen parameterγof iron and obtained the resultγ0ρ0=γρ=const,withγ0=1.945 andρ0=7.856g/cm^(3),ρbeing the density.

Opacity of Shock-Generated Argon Plasmas

Argon plasmas with uniform density and temperature are generated by a planar shock wave through argon gas.The opacities of argon plasma,covering the thermodynamic states at temperature of 1.4-2.2eV and in density of 0.0083-0.015g/cm^(3),are investigated by measuring the emitted radiance versus time at several visible wavelengths.Comparison of the measured opacities with the calculated ones demonstrates that the average atom model can be used well to describe the essential transport behaviour of photons in argon plasma under the above-mentioned thermodynamic condition.A simplified and self-consistent method to deduce the reflectivity R(λ)at the baseplate surface is applied.It demonstrates that the values of R(λ)are all around 0.4 in the experiments,which are basically in agreement with those given by Erskine previously(1994 J.Quant.Spectrosc.Radiat.Transfer 5197.)

Sound Velocities in Porous Iron Shocked to 177GPa and the Implications for Shock Melting

Sound velocities in shock-loaded solids are not only important to determine bulk moduli of solids at high pressures, but are also crucial to inform the shock melting of solids upon loading. In this letter, we first report on shock melting of porous solids at high pressures by measuring sound velocities in the porous iron of average density 6.90 g/cm^(3) in the pressure range of 110-180 GPa. The measured sound velocity softens at pressures from 122 to 156 Gpa, which may be attributed to shock melting of the porous iron.