Units accessed through ZIO and opened in FILEOP
	    -----------------------------------------------

Name            Extension	Comment

IO_AMAT		amat		Temporary storage for analytic Hessian

IO_AOINTS	aoints		Output: title, symmetry information, 
				Nuclear repulsion energy, unit matrix 
				(overlap), one electron hamiltonian, 
				2 electron integrals

IO_BVEC		bvec		Used in geometry optimization

IO_CI_MATRICES	cimat		This holds the CI coefficients, CI matrix 
				and CI overlap matrix in the rumer CI. See 
				subroutine VBINO.

IO_CON		con		Current connection info (output)

IO_CPY		cpx		Used in geometry optimization
IO_CPY		cpy		Used in geometry optimization
IO_CPZ		cpz		Used in geometry optimization

IO_DENSEXT	densext		See IO_SCF_DENSITY

IO_DOC		smry		Geometry optimization summary

IO_GRAD		grad		Gradients in update and step.

IO_INTFORCE	intforce	Forces in internal coordinates

IO_ITP7		itp7		Used in Rumer C.I. via WRTPRP

IO_IUNTHE	iunthe		Used in Spin-orbit calculations via WRTPRP

IO_MOMENTS	moments		Dipole, quadrupole, and higher moments
				in various basis sets; also a matrix
				called 'TRANSF C'

IO_OPTPOL	optpol		Old point, gradient, and Hessian in
				geometry optimization;
				Temporary storage in polarizabilities
				(POLIZ-DENA-DENB)

IO_PART_TRANS   part_trn	Used in htrn, zdotrn and hlftrn to store
				partially formed Fock matrices and integral
				transformation

IO_RUMER	rumer		Used in various (not necessarily Rumer) C.I.
				subroutines.

IO_ROHF_MATRICES rohf_mat	Used in fillfr to store open-shell Fock 
				matrices.

IO_SAVE		save		Temporary storage for analytic Hessian

IO_SCF_DENSITY	scf_den		Extrapolated densities for SCF; with unit
				IO_DENSEXT

IO_SCF_MATRICES	scfmat		Weighted overlap, Overlap, S**-1/2, One 
				electron matrix, first Fock operator, 
				second Fock op, etc


IO_1SETDOT	setdot		Temporary storage for analytic Hessian
IO_2SETDOT	setdot		Temporary storage for analytic Hessian

IO_TRNDEN	trnden		Unit for TRNDEN (read in INDENS): stores
				densities

IO_UVEC		uvec		Used in geometry optimization

IO_VEC_DEN	vecden		Vectors and densities for SCF

IO_XINDO	xindo		Used in XINDO and ab-initio to hold the 
				density matrices in the overlapping basis, 
				closed-shell (RHF) or closed shell than 
				alpha (UHF), or closed-shell, first 
				open-shell, second open-shell, etc. (ROHF) 
				These are followed by the appropriate
				m.o. coefficient matrices.

	    Units held local to particular subroutines
            ------------------------------------------

Name		Filename	Subroutine & comments


IO_1BWUB	ONAME.1bwub	pele, bwub: intermediate storage
                                pelefr, bwubfr: intermediate storage

IO_2BWUB	ONAME.2bwub	pele, bwub: intermediate storage
				pelefr, cphf1: intermediate storage

IO_3BWUB	ONAME.3bwub	pele, bwub, schmid: intermediate storage
				pelefr, bwubfr: intermediate storage

IO_CI_SYM	ONAME.ci_sym	sketch & cibonds: store intermediate infor-
				mation for CI with symmetry

IO_CPHF		ONAME.cphf	pelefr, cphf1: intermediate storage

IO_DRTDAT	(various)	drtdat; various output files

IO_HYPER(1..3)	ONAME.hyper1,2,3 pele, pelefr, hymodip, cphf1. Occ-occ and
				virt-virt dipoles with labels

IO_OCCDIP	ONAME.occdip	pele, pelefr, hymodip, cphf1. Occ-virt dipoles

IO_PELE		ONAME.pele	pele, hyper: intermediate storage

IO_PRPA		ONAME_rpa.DAT	prpa

IO_SELFEN	ONAME_sel.DAT	selfen

IO_2SHG2	ONAME.2shg2	spectr, shg4 (shg2.f) : exchange codetors 
				between these subroutines.

IO_SOLVFILE	SOLNAM_solvent.file  confin: write solvent data for dispersion
				     trnmom: write solvent data for dispersion
				     cidisp: read  solvent data for dispersion

IO_SYMORB	-		Used in symmk (symorb.f) but never actually 
				accessed. Not clear.