Here are a few choices:

awk '{split($0, a, /\//); print $0 "\t" a[2]}' file
awk -F/ -v OFS="\t" '{print $0, $2}' file

sed -r 's#^([^/]*/([^/]*)/.*)#\1\t\2#' file
sed 's#^\([^/]*/\([^/]*\)/.*\)#\1\t\2#' file
sed 'p; s#[^/]*/##; s#/.*##' file | paste - -

perl -F/ -lane 'print "$_\t$F[1]"' file


Extract text between two slashes and add it at the end of the line after a tab character
According to quantum mechanics, for multi-electron atoms, a single electron around the nuclei can be in the state of linear combination of different eigen energy states. In that case, even the energy of the electron is not one of the eigen energies.

In chemistry, we often say that an electron is in an orbital (such as 1s, 2s), another electron is in another orbital, etc. How does it make sense if an electron is in a linear combination state?
