The additional parameters are read from the species record. There is no range record nor an ENDS record for the HARM potential. The record is used to input parameters which describe the self energy of the shell. In the conventional shell model, this is just the dipole energy of the separated core and shell. In the ellipsoidal shell model it includes terms for the self energy due to breathing and distortion of the shell. The analytic form of the dipole part of the potential is
,
and 
must
be read from the species record. Their units are given below
- is
in eV
- is
in eV
- is
in eV
The
and operands
are optional. If omitted, their values are set equal to zero. If the ellipsoidal
shell model is being used, the
and parameters
must be included and set equal to zero if not used. Either two or four
additional parameters are required on the species record. These parameters
are, in order, two ellipsoidal force constants and two optional anharmonic
parameters. The form of the ellipsoid self energy is.
Where
The units of
= Distance of ellipsoid surface from centre along the principle axes
= Radius of ion i
and 
are given below
- is
in eV
is
dimensionless.
is a force constant for a pure ellipsoidal distortion and 
is a force constasnt for pure breathing distortion. If either of these distortions
is not required then the force constant should be set equal to a large number.
(A value of 1000.0 would be appropriate.)
controls how anharmonic the potential is. The default value if the parameters
are omitted is 4.0. The energy will diverge as 
approaches 
(from an initial infinite value) for pure ellipsoidal distortion or as 
approaches
for
pure breathing, again from an initial infinite value for no breathing. A
value of 1.0 gives no anharmonicity. LABELA and LABELB on the species record
must be the core and shell of the same ion. Printed output
HARMONIC CORE-SHELL INTERACTION BETWEEN SPECIES Labeli AND Labelj THIS HAS THE FORM V(R) = 1/2*K1*R**2 + 1/24*K2*R**4 + 1/720*K3*R**6 K1 = k1 K2 = k2 K3 = k3If the ions are ellipsoidal, the following is printed.
THESE SPECIES ALSO HAVE AN ELLIPSOID FORCE CONSTANT KEL THE FORM OF THE ELLIPSOID ENERGY IS E = 1/2 * KEL1 * (H-G) / ( 1 - 4/9 * (H-G)/RCAT**2) + 1/2 * KEL2 * (H+2G) / (1 - 4/9 * (H+2G)/RCAT**2) H = H1**2 + H2**2 + H3**2 G = H1*H2 + H1*H3 + H2*H3 THE FORCE CONSTANTS ARE kel1 kel2
Error messages
ERROR - A HARMONIC CORE-SHELL INTERACTION MUST BE BETWEEN THE CORE AND SHELL OF THE SAME ION
ERROR - THE MAXIMUM NUMBER OF MAXHAR HARMONIC CORE-SHELL POTENTIALS HAS BEEN EXCEEDED