檢視 $useaffinity 的原始碼

The program used the band offset ratio to calculate the energy difference between two material. However, the user can use the affinity command to override the use of band offset ratio 

For two different materials,the <math>\Delta Ec =  offset \times (Eg_{A}-Eg_{B} ) </math>. It will be changed to <math>\Delta Ec =  \chi_{A}-\chi_{B}) </math>