Interchain couplings in dimer approximation
from oligomer HOMO by PBE-D3paw900/CAM-B3LYPp2p
-----------------------------
    shift 1+2  1+1c  dE
          meV  meV  meV/mol
-----------------------------
aH  .000   26  -12   11
ax  .143  -29  -13    0.1
a   .150  -32  -13    0
o2  .152  -45  +13
ay  .167  -40  -13    0.5
o6  .169  -48   -8
o4  .180  -55   -2
c   .250  -61  -10    2.5
b   .311  -33   -7    6
bH  .500   79  -12   24
-----Oligomer polymorphs-----
o4aL    -19/27 -26