$buffer-constant-A(T)

Constant \(A(T)\) used for buffer calculations: The \({\text p}K_{\text a}\) value depends on the ionic strength.

$buffer-constant-A(T)                             optional
 constant-Centigrade-to-Kelvin    double          required
 T_A(T)                           double_array    required
$end_buffer-constant-A(T)                         optional

Example 1

!-------------------------------------------------------------!
$buffer-constant-A(T)                                         !
 constant-Centigrade-to-Kelvin = 273.15                       ! Kelvin = Celsius + 273.15
                                                              !
 !============================================================!
 !                  first column: T[C]   second column: A(T)  !
 !============================================================!
 T_A(T)                        =   0.0         0.4918         !   0° C = 273.15 K
                                  10.0         0.4989         !  10° C = 283.15 K
                                  20.0         0.5070         !  20° C = 293.15 K
                                  25.0         0.5114         !  25° C = 298.15 K
                                  30.0         0.5161         !  30° C = 303.15 K
$end_buffer-constant-A(T)                                     !
!-------------------------------------------------------------!

Example 2

!-------------------------------------------------------------!
$buffer-constant-A(T)                                         !
 constant-Centigrade-to-Kelvin = 273.15                       ! Kelvin = Celsius + 273.15
                                                              !
 !============================================================!
 !                  first column: T[C]   second column: A(T)  !
 !============================================================!
 T_A(T)                        =  25.0         0.5114         !  25° C = 298.15 K
$end_buffer-constant-A(T)                                     !
!-------------------------------------------------------------!

If the keyword $buffer-constant-A(T) is present in the input file, the values for the keyword $buffer-constant-A(T) in the database are overwritten.

It is possible to specify only one pair of “T, A(T)” values as shown in Example 2.

For more details on the physical significance of this keyword, please have a look at the database section: $buffer-constant-A(T)