8 use,
intrinsic :: iso_fortran_env, only: dp => real64
10 real(dp),
parameter :: &
11 pi=3.1415926535897932384626433832795028841971693993751058209749445923&
12 &078164062862089986280348253421170679_dp,& !<pi
13 sigmab=5.67037321e-8_dp,&
14 kb=1.380648813e-23_dp,&