QChem - Revision history

Cak49 at 14:22, 27 July 2021

2021-07-27T14:22:02Z

← Older revision		Revision as of 14:22, 27 July 2021
Line 154:		Line 154:
	Saving Minimum 4: -112.3571993219</pre>		Saving Minimum 4: -112.3571993219</pre>

	Information about the resulting NOCI states is printed at the end of the output file. In this example, the energies and S2 values can be examined with		Information about the resulting NOCI states is printed at the end of the output file. In this example, the energies and S^2 values can be examined with

	<pre>grep -A5 "NOCI Energy" formaldehyde.noci.out</pre>		<pre>grep -A5 "NOCI Energy" formaldehyde.noci.out</pre>
Line 206:		Line 206:
	NOCI_DETGEN 0		NOCI_DETGEN 0
	SKIP_SCFMAN TRUE		SKIP_SCFMAN TRUE
			SYMMETRY OFF
	$end		$end

Line 225:		Line 226:
	Total Energy = -111.8200841138</pre>		Total Energy = -111.8200841138</pre>

	and examine the energies and S2 values of the NOCI solutions with		and examine the energies and S^2 values of the NOCI solutions with

	<pre>grep -A5 "NOCI Energy" noci_form_1234.g0.xc0.out</pre>		<pre>grep -A5 "NOCI Energy" noci_form_1234.g0.xc0.out</pre>
Line 238:		Line 239:
	1 0.0000000 0.0000000 1.0107832 1.9977364</pre>		1 0.0000000 0.0000000 1.0107832 1.9977364</pre>

	(N.B. If we compare the NOCI states from method #1 and method #2, we notice that they are different because ~~weused~~ different HF states in both methods. If we had used the same states in both examples, we would get the same NOCI results.)		(N.B. If we compare the NOCI states from method #1 and method #2, we notice that they are different because we used different HF states in both methods. If we had used the same states in both examples, we would get the same NOCI results.)

	===Further Information===		===Further Information===

Cak49: Fixed formatting, other small changes

2021-07-24T21:19:18Z

Fixed formatting, other small changes

← Older revision		Revision as of 21:19, 24 July 2021
Line 1:		Line 1:
	Q-Chem is a commercial quantum chemistry package available for use in our group.		Q-Chem is a commercial quantum chemistry package available for use in our group.

	= Fragment Guesses with multiple bases =		==Fragment Guesses with multiple bases==
	To ~~uses~~ basis set projection and fragment guesses you have to run the smaller basis set calculation with fragments first, and then read this into a second calculation which does the projection		To use basis set projection and fragment guesses you have to run the smaller basis set calculation with fragments first, and then read this into a second calculation which does the projection
		⚫	<pre>$molecule
	<code>
⚫	$molecule
	0 1		0 1
	--		--
Line 15:		Line 14:
	He 10000 0 0		He 10000 0 0
	$end		$end

	$rem		$rem
	JOBTYPE sp		JOBTYPE sp
Line 24:		Line 24:
	SYM_IGNORE true		SYM_IGNORE true
	$end		$end

	@@@		@@@

	$molecule		$molecule
	read		read
	$end		$end

	$rem		$rem
	scf_guess read		scf_guess read
Line 39:		Line 42:
	SYM_IGNORE true		SYM_IGNORE true
	basisprojtype ovprojection		basisprojtype ovprojection
	$end		$end</pre>
	</code>

	==INTDUMP / FCIDUMP ==		==INTDUMP / FCIDUMP ==

	To create files in the FCIDUMP format (used e.g. by Hande) create a QChem input file:		To create files in the FCIDUMP format (used e.g. by Hande) create a QChem input file:

	<pre>		<pre>
	$molecule		$molecule
Line 89:		Line 89:

	==Troubleshooting SCF Metadynamics Calculations==		==Troubleshooting SCF Metadynamics Calculations==

			A full example for SCF Metadynamics can be found at [https://wikis.ch.cam.ac.uk/thom/wiki/index.php/QCMagic QCMagic SymmetryTools Tutorial (Section 7.1)]. This section provides more information on how to choose parameters in different situations.

	If a calculation repeatedly converges on the same solution, adjusting one or more of these keywords can help to find different solutions.		If a calculation repeatedly converges on the same solution, adjusting one or more of these keywords can help to find different solutions.

	* Increasing <code>SCF_MINFIND_INITNORM</code>, <code>SCF_MINFIND_INITLAMBDA</code> and <code>SCF_MINFIND_INCREASEFACTOR</code> can help get out of the minimum. However, setting <code>SCF_MINFIND_INITLAMBDA</code> too high can result in SCF solutions with very high energies, and <code>SCF_MINFIND_INITNORM</code> can get in the way of convergence, particularly when reading in a solution (in that case, set it to zero).		* Increasing <code>SCF_MINFIND_INITNORM</code>, <code>SCF_MINFIND_INITLAMBDA</code> and <code>SCF_MINFIND_INCREASEFACTOR</code> can help get out of the minimum. However, setting <code>SCF_MINFIND_INITLAMBDA</code> too high can result in SCF solutions with very high energies, and <code>SCF_MINFIND_INITNORM</code> can get in the way of convergence, particularly when reading in a solution (in that case, set it to zero).
	* Increasing <code>SCF_MINFIND_RESTARTSTEPS</code> helps if a solution is close to another minima but does not converge before the calculation restarts with new orbitals		* Increasing <code>SCF_MINFIND_RESTARTSTEPS</code> helps if a solution is close to another minima but does not converge before the calculation restarts with new orbitals
	* Changing <code>SCF_MINFIND_RANDOMMIXING</code> is generally helpful. +/- 15708 and 31416 are sensible values to try, and 07854 (which corresponds to halfway between swapping the orbitals) can also help.		* Changing <code>SCF_MINFIND_RANDOMMIXING</code> is generally helpful. +/- 15708 and 31416 are sensible values to try, and 07854 (which corresponds to halfway between swapping the orbitals) can also help.


	If the resulting solutions are too high in energy,		If the resulting solutions are too high in energy,

Cak49: Added NOCI Tutorial

2021-07-24T21:12:59Z

Added NOCI Tutorial

Show changes

Zw357: /* Troubleshooting SCF Metadynamics Calculations */

2021-07-20T09:00:47Z

Troubleshooting SCF Metadynamics Calculations

← Older revision		Revision as of 09:00, 20 July 2021
Line 92:		Line 92:
	If a calculation repeatedly converges on the same solution, adjusting one or more of these keywords can help to find different solutions.		If a calculation repeatedly converges on the same solution, adjusting one or more of these keywords can help to find different solutions.

	* Increasing <code>SCF_MINFIND_INITNORM</code>, <code>SCF_MINFIND_INITLAMBDA</code> and <code>~~SCF_MINFIND_INREASEFACTOR~~</code> can help get out of the minimum. However, setting <code>SCF_MINFIND_INITLAMBDA</code> too high can result in SCF solutions with very high energies, and <code>SCF_MINFIND_INITNORM</code> can get in the way of convergence, particularly when reading in a solution (in that case, set it to zero).		* Increasing <code>SCF_MINFIND_INITNORM</code>, <code>SCF_MINFIND_INITLAMBDA</code> and <code>SCF_MINFIND_INCREASEFACTOR</code> can help get out of the minimum. However, setting <code>SCF_MINFIND_INITLAMBDA</code> too high can result in SCF solutions with very high energies, and <code>SCF_MINFIND_INITNORM</code> can get in the way of convergence, particularly when reading in a solution (in that case, set it to zero).
	* Increasing <code>SCF_MINFIND_RESTARTSTEPS</code> helps if a solution is close to another minima but does not converge before the calculation restarts with new orbitals		* Increasing <code>SCF_MINFIND_RESTARTSTEPS</code> helps if a solution is close to another minima but does not converge before the calculation restarts with new orbitals
	* Changing <code>SCF_MINFIND_RANDOMMIXING</code> is generally helpful. +/- 15708 and 31416 are sensible values to try, and 07854 (which corresponds to halfway between swapping the orbitals) can also help.		* Changing <code>SCF_MINFIND_RANDOMMIXING</code> is generally helpful. +/- 15708 and 31416 are sensible values to try, and 07854 (which corresponds to halfway between swapping the orbitals) can also help.

Cak49: Added section on troubleshooting SCF metadynamics

2021-07-12T21:16:00Z

Added section on troubleshooting SCF metadynamics

← Older revision		Revision as of 21:16, 12 July 2021
Line 87:		Line 87:
	0.52917721026434 0 0 0 0		0.52917721026434 0 0 0 0
	</pre>		</pre>

			==Troubleshooting SCF Metadynamics Calculations==

			If a calculation repeatedly converges on the same solution, adjusting one or more of these keywords can help to find different solutions.

			* Increasing <code>SCF_MINFIND_INITNORM</code>, <code>SCF_MINFIND_INITLAMBDA</code> and <code>SCF_MINFIND_INREASEFACTOR</code> can help get out of the minimum. However, setting <code>SCF_MINFIND_INITLAMBDA</code> too high can result in SCF solutions with very high energies, and <code>SCF_MINFIND_INITNORM</code> can get in the way of convergence, particularly when reading in a solution (in that case, set it to zero).
			* Increasing <code>SCF_MINFIND_RESTARTSTEPS</code> helps if a solution is close to another minima but does not converge before the calculation restarts with new orbitals
			* Changing <code>SCF_MINFIND_RANDOMMIXING</code> is generally helpful. +/- 15708 and 31416 are sensible values to try, and 07854 (which corresponds to halfway between swapping the orbitals) can also help.


			If the resulting solutions are too high in energy,
			* decreasing <code>SCF_MINFIND_INITNORM</code>
			* decreasing <code>SCF_MINFIND_INITLAMBDA</code>
			* decreasing <code>SCF_MINFIND_MIXENERGY</code> (even to 00005)
			* adjusting <code>MOM_START</code>
			* and using <code>SCF_MINFIND_MIXMETHOD</code> 1 or 2
			can help to find lower-energy excited states.

Ghb29: Document producing INTDUMP files

2020-02-20T15:53:18Z

Document producing INTDUMP files

← Older revision		Revision as of 15:53, 20 February 2020
Line 41:		Line 41:
	$end		$end
	</code>		</code>

			==INTDUMP / FCIDUMP ==

			To create files in the FCIDUMP format (used e.g. by Hande) create a QChem input file:

			<pre>
			$molecule
			0 1
			H 0 0 0
			H 1 0 0
			$end

			$rem
			correlation idump
			exchange hf
			basis sto-3G
			use_abelian_subgroup true
			scf_guess_print 9999
			$end
			</pre>

			and use the version of QChem currently (2020-02-20) available from:
			<pre>
			[you@liminal] $ export QC=public_o
			[you@liminal] $ source ~ajwt3/code/qchem/qcsetup.bash
			[you@liminal] $ qchem your-input-file.in
			</pre>

			This should produce a file called <code>INTDUMP</code>
			<pre>
			&FCI NORB= 2,NELEC= 2,MS2= 0
			ORBSYM=1,6,
			ISYM=1 UHF=.FALSE.
			&END
			0.62640249948715 1 1 1 1
			0.19679058349422 1 2 1 2
			0.6217067630807 2 2 1 1
			0.19679058349422 2 1 1 2
			0.19679058349422 2 1 2 1
			0.65307074688898 2 2 2 2
			-1.1108441795661 1 1 0 0
			-0.58912100326925 2 2 0 0
			-0.39980670964291 1 0 0 0
			0.37823811728909 2 0 0 0
			0.52917721026434 0 0 0 0
			</pre>

Ajwt3 at 12:09, 17 January 2020

2020-01-17T12:09:51Z

← Older revision		Revision as of 12:09, 17 January 2020
Line 1:		Line 1:
	Q-Chem is a commercial quantum chemistry package available for use in our group.		Q-Chem is a commercial quantum chemistry package available for use in our group.

	Fragment Guesses with multiple bases		= Fragment Guesses with multiple bases =
	------------------------------------
	To uses basis set projection and fragment guesses you have to run the smaller basis set calculation with fragments first, and then read this into a second calculation which does the projection		To uses basis set projection and fragment guesses you have to run the smaller basis set calculation with fragments first, and then read this into a second calculation which does the projection
	<code>		<code>

Ajwt3 at 12:08, 17 January 2020

2020-01-17T12:08:53Z

← Older revision		Revision as of 12:08, 17 January 2020
Line 1:		Line 1:
	Q-Chem is a commercial quantum chemistry package available for use in our group.		Q-Chem is a commercial quantum chemistry package available for use in our group.

			Fragment Guesses with multiple bases
			------------------------------------
			To uses basis set projection and fragment guesses you have to run the smaller basis set calculation with fragments first, and then read this into a second calculation which does the projection
			<code>
			$molecule
			0 1
			--
			0 1
			H 0.000000 -0.115747 1.133769
			H 0.000000 1.109931 -0.113383
			O 0.000000 0.005817 -0.020386
			--
			0 1
			He 10000 0 0
			$end
			$rem
			JOBTYPE sp
			EXCHANGE b3lyp
			BASIS cc-pVDZ
			scf_guess fragmo
			CORRELATION none
			SYMMETRY false
			SYM_IGNORE true
			$end
			@@@
			$molecule
			read
			$end
			$rem
			scf_guess read
			JOBTYPE sp
			EXCHANGE b3lyp
			BASIS cc-pVTZ
			BASIS2 cc-pVDZ
			CORRELATION none
			MAX_SCF_CYCLES 600
			SYMMETRY false
			SYM_IGNORE true
			basisprojtype ovprojection
			$end
			</code>

Hb407: Created page with "Q-Chem is a commercial quantum chemistry package available for use in our group."

2018-08-09T10:59:13Z

Created page with "Q-Chem is a commercial quantum chemistry package available for use in our group."

New page

Q-Chem is a commercial quantum chemistry package available for use in our group.