From owner-chemistry@ccl.net Mon Jan 8 12:47:01 2024 From: "David Shobe shobedavid .. gmail.com" To: CCL Subject: CCL: wavefunction instability Message-Id: <-55075-240108124232-30188-lYf27eSbXecY7uGDy7ZtbA[#]server.ccl.net> X-Original-From: David Shobe Content-Type: multipart/alternative; boundary="00000000000051c14d060e72b88d" Date: Mon, 8 Jan 2024 11:42:11 -0600 MIME-Version: 1.0 Sent to CCL by: David Shobe [shobedavid[]gmail.com] --00000000000051c14d060e72b88d Content-Type: text/plain; charset="UTF-8" This happens to me often. I have a calculation, but after checking wavefunction stability, it turns out to be unstable. So I use guess=(read,alter) or its equivalent to manipulate the orbitals, and run the calculation again. Only I get the same result: same energy, same instability. What is going on and what should I do in this circumstance? Regards, --David Shobe --00000000000051c14d060e72b88d Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

This happens to me often. I have a calculation, but after = checking wavefunction stability, it turns out to be unstable. So I use gues= s=3D(read,alter) or its equivalent to manipulate the orbitals, and run the = calculation again. Only I get the same result: same energy, same instabilit= y.

What is going on and what should I do in this circums= tance?

Regards,

--David Shobe

--00000000000051c14d060e72b88d-- From owner-chemistry@ccl.net Mon Jan 8 14:33:01 2024 From: "Cory Pye Cory.Pye]![smu.ca" To: CCL Subject: CCL: wavefunction instability Message-Id: <-55076-240108142559-4249-Izd4amwwRwsDcAZNjg84uQ{:}server.ccl.net> X-Original-From: Cory Pye Content-Language: en-CA Content-Type: multipart/alternative; boundary="_000_YT2PR01MB412580DD369FF8D9204A9A8BF86B2YT2PR01MB4125CANP_" Date: Mon, 8 Jan 2024 19:25:48 +0000 MIME-Version: 1.0 Sent to CCL by: Cory Pye [Cory.Pye]~[smu.ca] --_000_YT2PR01MB412580DD369FF8D9204A9A8BF86B2YT2PR01MB4125CANP_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable David, Are you using an unrestricted wavefunction in all cases? For an even # of e= lectrons, it defaults to a restricted wavefunction if not explicitly specif= ied. For rhf wavefunction, it will complain about an rhf to uhf instability= . Cory Get Outlook for Android ________________________________ > From: owner-chemistry+cory.pye=3D=3Dsmu.ca]-[ccl.net on behalf of David Shobe shobedavid .. gmail.com Sent: Monday, January 8, 2024 1:42:11 PM To: Cory Pye Subject: CCL: wavefunction instability This happens to me often. I have a calculation, but after checking wavefunc= tion stability, it turns out to be unstable. So I use guess=3D(read,alter) = or its equivalent to manipulate the orbitals, and run the calculation again= . Only I get the same result: same energy, same instability. What is going on and what should I do in this circumstance? Regards, --David Shobe --_000_YT2PR01MB412580DD369FF8D9204A9A8BF86B2YT2PR01MB4125CANP_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

David,

Are you using an unrestricted wavefunction in all cases? = For an even # of electrons, it defaults to a restricted wavefunc= tion if not explicitly specified. For rhf wavefunction, it will complain ab= out an rhf to uhf instability.

Cory

Get Outlook for Android

From: owner-chemistry+cory.= pye=3D=3Dsmu.ca]-[ccl.net <owner-chemistry+cory.pye=3D=3Dsmu.ca]-[ccl.net>= ; on behalf of David Shobe shobedavid .. gmail.com <owner-chemistry]-[ccl.= net>
Sent: Monday, January 8, 2024 1:42:11 PM
To: Cory Pye <Cory.Pye]-[smu.ca>
Subject: CCL: wavefunction instability

What is going on and what should I do in this circumstance?

Regards,

--David Shobe

--_000_YT2PR01MB412580DD369FF8D9204A9A8BF86B2YT2PR01MB4125CANP_-- From owner-chemistry@ccl.net Mon Jan 8 15:08:00 2024 From: "T. Daniel Crawford crawdad- -vt.edu" To: CCL Subject: CCL: wavefunction instability Message-Id: <-55077-240108144813-11607-nlT9w/0pg3mfbwKLk+5/jA]=[server.ccl.net> X-Original-From: "T. Daniel Crawford" Content-Type: multipart/alternative; boundary="000000000000c01da2060e747993" Date: Mon, 8 Jan 2024 14:47:50 -0500 MIME-Version: 1.0 Sent to CCL by: "T. Daniel Crawford" [crawdad * vt.edu] --000000000000c01da2060e747993 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Does your system have any point group symmetry, and, if so, does the wave function stability analysis categorize the instabilities by irrep? If so, then you can only follow the instability if you break the relevant symmetry. Otherwise you'll always converge to the totally symmetric solution. -Daniel -- Prof. T. Daniel Crawford crawdad . vt.edu On Mon, Jan 8, 2024 at 1:18=E2=80=AFPM David Shobe shobedavid .. gmail.com = < owner-chemistry . ccl.net> wrote: > This happens to me often. I have a calculation, but after checking > wavefunction stability, it turns out to be unstable. So I use > guess=3D(read,alter) or its equivalent to manipulate the orbitals, and ru= n > the calculation again. Only I get the same result: same energy, same > instability. > > What is going on and what should I do in this circumstance? > > Regards, > --David Shobe > > --000000000000c01da2060e747993 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Does your system have any point group symmetry, and, if so= , does the wave function stability analysis categorize the instabilities by= irrep?=C2=A0 If so, then you can only follow the instability if you break = the relevant symmetry.=C2=A0 Otherwise you'll always converge to the to= tally symmetric solution.

-Daniel

Prof. T. Daniel Crawford

crawdad . vt.edu

On Mon, Jan 8, 2024 at 1:18=E2=80=AFPM David Shobe shobedav= id .. gmail.com <owner-chemistry . ccl.net> wrote:

This happens t= o me often. I have a calculation, but after checking wavefunction stability= , it turns out to be unstable. So I use guess=3D(read,alter) or its equival= ent to manipulate the orbitals, and run the calculation again. Only I get t= he same result: same energy, same instability.

What is g= oing on and what should I do in this circumstance?

Regards,

--David Shobe

--000000000000c01da2060e747993-- From owner-chemistry@ccl.net Mon Jan 8 16:35:00 2024 From: "=?utf-8?B?SsO8cmdlbiBHcsOkZmVuc3RlaW4=?= jurgen.grafenstein(_)chem.gu.se" To: CCL Subject: CCL: wavefunction instability Message-Id: <-55078-240108163347-29442-fuGZK7JBaxW/9fDBUWQrMg+/-server.ccl.net> X-Original-From: =?utf-8?B?SsO8cmdlbiBHcsOkZmVuc3RlaW4=?= Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_6FAAA7AA52644B26AED8475C29143FC7chemguse_" Date: Mon, 8 Jan 2024 21:33:21 +0000 MIME-Version: 1.0 Sent to CCL by: =?utf-8?B?SsO8cmdlbiBHcsOkZmVuc3RlaW4=?= [jurgen.grafenstein]|[chem.gu.se] --_000_6FAAA7AA52644B26AED8475C29143FC7chemguse_ Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 RGVhciBEYXZpZCwNCg0KQ291bGQgeW91IHByb3ZpZGUgYW4gZXhhbXBsZSBnZW9tZXRyeSBmb3Ig d2hpY2ggdGhlIGNhbGN1bGF0aW9uIHRoYXQgaGFzIGdvbmUgd3Jvbmc/DQoNClBvc3NpYmx5IHlv dSBuZWVkIHRvIHNwZWNpZnkgR3Vlc3M9TWl4IGluc3RlYWQgb2YgR3Vlc3M9QWx0ZXI7IHRoZSB0 d28gb3B0aW9ucyBhcmUgbm90IGVxdWl2YWxlbnQgaW4gdGhlaXIgaW1wYWN0IG9uIHRoZSBjYWxj dWxhdGlvbi4NCg0KQmVzdCByZWdhcmRzLA0KSsO8cmdlbg0KDQpKw7xyZ2VuIEdyw6RmZW5zdGVp bg0KVW5pdmVyc2l0eSBvZiBHb3RoZW5idXJnDQpEZXBhcnRtZW50IG9mIENoZW1pc3RyeSBhbmQg TW9sZWN1bGFyIEJpb2xvZ3kNCkJveCA0NjINClNFLTQwNSAzMCBHw7Z0ZWJvcmcsIFN3ZWRlbg0K DQpGcm9tOiA8b3duZXItY2hlbWlzdHJ5K2p1cmdlbi5ncmFmZW5zdGVpbj09Y2hlbS5ndS5zZUBj Y2wubmV0PiBvbiBiZWhhbGYgb2YgIkRhdmlkIFNob2JlIHNob2JlZGF2aWQgLi4gZ21haWwuY29t IiA8b3duZXItY2hlbWlzdHJ5QGNjbC5uZXQ+DQpSZXBseS1UbzogQ0NMIFN1YnNjcmliZXJzIDxj aGVtaXN0cnlAY2NsLm5ldD4NCkRhdGU6IE1vbmRheSwgOCBKYW51YXJ5IDIwMjQgYXQgMjA6NDMN ClRvOiBKw7xyZ2VuIEdyw6RmZW5zdGVpbiA8anVyZ2VuLmdyYWZlbnN0ZWluQGNoZW0uZ3Uuc2U+ DQpTdWJqZWN0OiBDQ0w6IHdhdmVmdW5jdGlvbiBpbnN0YWJpbGl0eQ0KDQpUaGlzIGhhcHBlbnMg dG8gbWUgb2Z0ZW4uIEkgaGF2ZSBhIGNhbGN1bGF0aW9uLCBidXQgYWZ0ZXIgY2hlY2tpbmcgd2F2 ZWZ1bmN0aW9uIHN0YWJpbGl0eSwgaXQgdHVybnMgb3V0IHRvIGJlIHVuc3RhYmxlLiBTbyBJIHVz ZSBndWVzcz0ocmVhZCxhbHRlcikgb3IgaXRzIGVxdWl2YWxlbnQgdG8gbWFuaXB1bGF0ZSB0aGUg b3JiaXRhbHMsIGFuZCBydW4gdGhlIGNhbGN1bGF0aW9uIGFnYWluLiBPbmx5IEkgZ2V0IHRoZSBz YW1lIHJlc3VsdDogc2FtZSBlbmVyZ3ksIHNhbWUgaW5zdGFiaWxpdHkuDQoNCldoYXQgaXMgZ29p bmcgb24gYW5kIHdoYXQgc2hvdWxkIEkgZG8gaW4gdGhpcyBjaXJjdW1zdGFuY2U/DQoNClJlZ2Fy ZHMsDQotLURhdmlkIFNob2JlDQoNCg== --_000_6FAAA7AA52644B26AED8475C29143FC7chemguse_ Content-Type: text/html; charset="utf-8" Content-ID: Content-Transfer-Encoding: base64 PGh0bWwgeG1sbnM6bz0idXJuOnNjaGVtYXMtbWljcm9zb2Z0LWNvbTpvZmZpY2U6b2ZmaWNlIiB4 bWxuczp3PSJ1cm46c2NoZW1hcy1taWNyb3NvZnQtY29tOm9mZmljZTp3b3JkIiB4bWxuczptPSJo dHRwOi8vc2NoZW1hcy5taWNyb3NvZnQuY29tL29mZmljZS8yMDA0LzEyL29tbWwiIHhtbG5zPSJo dHRwOi8vd3d3LnczLm9yZy9UUi9SRUMtaHRtbDQwIj4NCjxoZWFkPg0KPG1ldGEgaHR0cC1lcXVp dj0iQ29udGVudC1UeXBlIiBjb250ZW50PSJ0ZXh0L2h0bWw7IGNoYXJzZXQ9dXRmLTgiPg0KPG1l dGEgbmFtZT0iR2VuZXJhdG9yIiBjb250ZW50PSJNaWNyb3NvZnQgV29yZCAxNSAoZmlsdGVyZWQg bWVkaXVtKSI+DQo8c3R5bGU+PCEtLQ0KLyogRm9udCBEZWZpbml0aW9ucyAqLw0KQGZvbnQtZmFj ZQ0KCXtmb250LWZhbWlseToiQ2FtYnJpYSBNYXRoIjsNCglwYW5vc2UtMToyIDQgNSAzIDUgNCA2 IDMgMiA0O30NCkBmb250LWZhY2UNCgl7Zm9udC1mYW1pbHk6Q2FsaWJyaTsNCglwYW5vc2UtMToy IDE1IDUgMiAyIDIgNCAzIDIgNDt9DQovKiBTdHlsZSBEZWZpbml0aW9ucyAqLw0KcC5Nc29Ob3Jt YWwsIGxpLk1zb05vcm1hbCwgZGl2Lk1zb05vcm1hbA0KCXttYXJnaW46MGNtOw0KCW1hcmdpbi1i b3R0b206LjAwMDFwdDsNCglmb250LXNpemU6MTEuMHB0Ow0KCWZvbnQtZmFtaWx5OiJDYWxpYnJp IixzYW5zLXNlcmlmO30NCmE6bGluaywgc3Bhbi5Nc29IeXBlcmxpbmsNCgl7bXNvLXN0eWxlLXBy aW9yaXR5Ojk5Ow0KCWNvbG9yOiMwNTYzQzE7DQoJdGV4dC1kZWNvcmF0aW9uOnVuZGVybGluZTt9 DQphOnZpc2l0ZWQsIHNwYW4uTXNvSHlwZXJsaW5rRm9sbG93ZWQNCgl7bXNvLXN0eWxlLXByaW9y aXR5Ojk5Ow0KCWNvbG9yOiM5NTRGNzI7DQoJdGV4dC1kZWNvcmF0aW9uOnVuZGVybGluZTt9DQpw Lm1zb25vcm1hbDAsIGxpLm1zb25vcm1hbDAsIGRpdi5tc29ub3JtYWwwDQoJe21zby1zdHlsZS1u YW1lOm1zb25vcm1hbDsNCgltc28tbWFyZ2luLXRvcC1hbHQ6YXV0bzsNCgltYXJnaW4tcmlnaHQ6 MGNtOw0KCW1zby1tYXJnaW4tYm90dG9tLWFsdDphdXRvOw0KCW1hcmdpbi1sZWZ0OjBjbTsNCglm b250LXNpemU6MTEuMHB0Ow0KCWZvbnQtZmFtaWx5OiJDYWxpYnJpIixzYW5zLXNlcmlmO30NCnNw YW4uRW1haWxTdHlsZTE4DQoJe21zby1zdHlsZS10eXBlOnBlcnNvbmFsLXJlcGx5Ow0KCWZvbnQt ZmFtaWx5OiJDYWxpYnJpIixzYW5zLXNlcmlmO30NCi5Nc29DaHBEZWZhdWx0DQoJe21zby1zdHls ZS10eXBlOmV4cG9ydC1vbmx5Ow0KCWZvbnQtc2l6ZToxMC4wcHQ7fQ0KQHBhZ2UgV29yZFNlY3Rp b24xDQoJe3NpemU6NjEyLjBwdCA3OTIuMHB0Ow0KCW1hcmdpbjo3MC44NXB0IDcwLjg1cHQgNzAu ODVwdCA3MC44NXB0O30NCmRpdi5Xb3JkU2VjdGlvbjENCgl7cGFnZTpXb3JkU2VjdGlvbjE7fQ0K LS0+PC9zdHlsZT4NCjwvaGVhZD4NCjxib2R5IGxhbmc9IlNWIiBsaW5rPSIjMDU2M0MxIiB2bGlu az0iIzk1NEY3MiI+DQo8ZGl2IGNsYXNzPSJXb3JkU2VjdGlvbjEiPg0KPHAgY2xhc3M9Ik1zb05v cm1hbCI+RGVhciBEYXZpZCw8bzpwPjwvbzpwPjwvcD4NCjxwIGNsYXNzPSJNc29Ob3JtYWwiPjxv OnA+Jm5ic3A7PC9vOnA+PC9wPg0KPHAgY2xhc3M9Ik1zb05vcm1hbCI+PHNwYW4gbGFuZz0iRU4t VVMiPkNvdWxkIHlvdSBwcm92aWRlIGFuIGV4YW1wbGUgZ2VvbWV0cnkgZm9yIHdoaWNoIHRoZSBj YWxjdWxhdGlvbiB0aGF0IGhhcyBnb25lIHdyb25nPw0KPG86cD48L286cD48L3NwYW4+PC9wPg0K PHAgY2xhc3M9Ik1zb05vcm1hbCI+PHNwYW4gbGFuZz0iRU4tVVMiPjxvOnA+Jm5ic3A7PC9vOnA+ PC9zcGFuPjwvcD4NCjxwIGNsYXNzPSJNc29Ob3JtYWwiPjxzcGFuIGxhbmc9IkVOLVVTIj5Qb3Nz aWJseSB5b3UgbmVlZCB0byBzcGVjaWZ5IEd1ZXNzPU1peCBpbnN0ZWFkIG9mIEd1ZXNzPUFsdGVy OyB0aGUgdHdvIG9wdGlvbnMgYXJlIG5vdCBlcXVpdmFsZW50IGluIHRoZWlyIGltcGFjdCBvbiB0 aGUgY2FsY3VsYXRpb24uPG86cD48L286cD48L3NwYW4+PC9wPg0KPHAgY2xhc3M9Ik1zb05vcm1h bCI+PHNwYW4gbGFuZz0iRU4tVVMiPjxvOnA+Jm5ic3A7PC9vOnA+PC9zcGFuPjwvcD4NCjxwIGNs YXNzPSJNc29Ob3JtYWwiPjxzcGFuIGxhbmc9IkVOLVVTIj5CZXN0IHJlZ2FyZHMsPG86cD48L286 cD48L3NwYW4+PC9wPg0KPHAgY2xhc3M9Ik1zb05vcm1hbCI+PHNwYW4gbGFuZz0iRU4tVVMiPkrD vHJnZW48bzpwPjwvbzpwPjwvc3Bhbj48L3A+DQo8ZGl2IHN0eWxlPSJtc28tZWxlbWVudDpwYXJh LWJvcmRlci1kaXY7Ym9yZGVyOm5vbmU7Ym9yZGVyLWJvdHRvbTpzb2xpZCB3aW5kb3d0ZXh0IDEu NXB0O3BhZGRpbmc6MGNtIDBjbSAxLjBwdCAwY20iPg0KPHAgY2xhc3M9Ik1zb05vcm1hbCIgc3R5 bGU9ImJvcmRlcjpub25lO3BhZGRpbmc6MGNtIj48c3BhbiBsYW5nPSJFTi1VUyI+PG86cD4mbmJz cDs8L286cD48L3NwYW4+PC9wPg0KPC9kaXY+DQo8cCBjbGFzcz0iTXNvTm9ybWFsIj48c3BhbiBs YW5nPSJFTi1VUyI+SsO8cmdlbiBHcsOkZmVuc3RlaW48bzpwPjwvbzpwPjwvc3Bhbj48L3A+DQo8 cCBjbGFzcz0iTXNvTm9ybWFsIj48c3BhbiBsYW5nPSJFTi1VUyI+VW5pdmVyc2l0eSBvZiBHb3Ro ZW5idXJnPG86cD48L286cD48L3NwYW4+PC9wPg0KPHAgY2xhc3M9Ik1zb05vcm1hbCI+PHNwYW4g bGFuZz0iRU4tVVMiPkRlcGFydG1lbnQgb2YgQ2hlbWlzdHJ5IGFuZCBNb2xlY3VsYXIgQmlvbG9n eTxvOnA+PC9vOnA+PC9zcGFuPjwvcD4NCjxwIGNsYXNzPSJNc29Ob3JtYWwiPjxzcGFuIGxhbmc9 IkVOLVVTIj5Cb3ggNDYyPG86cD48L286cD48L3NwYW4+PC9wPg0KPHAgY2xhc3M9Ik1zb05vcm1h bCI+PHNwYW4gbGFuZz0iRU4tVVMiPlNFLTQwNSAzMCBHw7Z0ZWJvcmcsIFN3ZWRlbjxvOnA+PC9v OnA+PC9zcGFuPjwvcD4NCjxwIGNsYXNzPSJNc29Ob3JtYWwiPjxzcGFuIGxhbmc9IkVOLVVTIj48 bzpwPiZuYnNwOzwvbzpwPjwvc3Bhbj48L3A+DQo8ZGl2IHN0eWxlPSJib3JkZXI6bm9uZTtib3Jk ZXItdG9wOnNvbGlkICNCNUM0REYgMS4wcHQ7cGFkZGluZzozLjBwdCAwY20gMGNtIDBjbSI+DQo8 cCBjbGFzcz0iTXNvTm9ybWFsIj48Yj48c3BhbiBzdHlsZT0iZm9udC1zaXplOjEyLjBwdDtjb2xv cjpibGFjayI+RnJvbTogPC9zcGFuPjwvYj48c3BhbiBzdHlsZT0iZm9udC1zaXplOjEyLjBwdDtj b2xvcjpibGFjayI+Jmx0O293bmVyLWNoZW1pc3RyeStqdXJnZW4uZ3JhZmVuc3RlaW49PWNoZW0u Z3Uuc2VAY2NsLm5ldCZndDsgb24gYmVoYWxmIG9mICZxdW90O0RhdmlkIFNob2JlIHNob2JlZGF2 aWQgLi4gZ21haWwuY29tJnF1b3Q7ICZsdDtvd25lci1jaGVtaXN0cnlAY2NsLm5ldCZndDs8YnI+ DQo8Yj5SZXBseS1UbzogPC9iPkNDTCBTdWJzY3JpYmVycyAmbHQ7Y2hlbWlzdHJ5QGNjbC5uZXQm Z3Q7PGJyPg0KPGI+RGF0ZTogPC9iPk1vbmRheSwgOCBKYW51YXJ5IDIwMjQgYXQgMjA6NDM8YnI+ DQo8Yj5UbzogPC9iPkrDvHJnZW4gR3LDpGZlbnN0ZWluICZsdDtqdXJnZW4uZ3JhZmVuc3RlaW5A Y2hlbS5ndS5zZSZndDs8YnI+DQo8Yj5TdWJqZWN0OiA8L2I+Q0NMOiB3YXZlZnVuY3Rpb24gaW5z dGFiaWxpdHk8bzpwPjwvbzpwPjwvc3Bhbj48L3A+DQo8L2Rpdj4NCjxkaXY+DQo8cCBjbGFzcz0i TXNvTm9ybWFsIj48bzpwPiZuYnNwOzwvbzpwPjwvcD4NCjwvZGl2Pg0KPGRpdj4NCjxwIGNsYXNz PSJNc29Ob3JtYWwiPlRoaXMgaGFwcGVucyB0byBtZSBvZnRlbi4gSSBoYXZlIGEgY2FsY3VsYXRp b24sIGJ1dCBhZnRlciBjaGVja2luZyB3YXZlZnVuY3Rpb24gc3RhYmlsaXR5LCBpdCB0dXJucyBv dXQgdG8gYmUgdW5zdGFibGUuIFNvIEkgdXNlIGd1ZXNzPShyZWFkLGFsdGVyKSBvciBpdHMgZXF1 aXZhbGVudCB0byBtYW5pcHVsYXRlIHRoZSBvcmJpdGFscywgYW5kIHJ1biB0aGUgY2FsY3VsYXRp b24gYWdhaW4uIE9ubHkgSSBnZXQNCiB0aGUgc2FtZSByZXN1bHQ6IHNhbWUgZW5lcmd5LCBzYW1l IGluc3RhYmlsaXR5LjxvOnA+PC9vOnA+PC9wPg0KPGRpdj4NCjxwIGNsYXNzPSJNc29Ob3JtYWwi PjxvOnA+Jm5ic3A7PC9vOnA+PC9wPg0KPC9kaXY+DQo8ZGl2Pg0KPHAgY2xhc3M9Ik1zb05vcm1h bCI+V2hhdCBpcyBnb2luZyBvbiBhbmQgd2hhdCBzaG91bGQgSSBkbyBpbiB0aGlzIGNpcmN1bXN0 YW5jZT88bzpwPjwvbzpwPjwvcD4NCjwvZGl2Pg0KPGRpdj4NCjxwIGNsYXNzPSJNc29Ob3JtYWwi PjxvOnA+Jm5ic3A7PC9vOnA+PC9wPg0KPC9kaXY+DQo8ZGl2Pg0KPHAgY2xhc3M9Ik1zb05vcm1h bCI+UmVnYXJkcyw8bzpwPjwvbzpwPjwvcD4NCjwvZGl2Pg0KPGRpdj4NCjxwIGNsYXNzPSJNc29O b3JtYWwiPi0tRGF2aWQgU2hvYmU8bzpwPjwvbzpwPjwvcD4NCjwvZGl2Pg0KPGRpdj4NCjxwIGNs YXNzPSJNc29Ob3JtYWwiPjxvOnA+Jm5ic3A7PC9vOnA+PC9wPg0KPC9kaXY+DQo8L2Rpdj4NCjwv ZGl2Pg0KPC9ib2R5Pg0KPC9odG1sPg0K --_000_6FAAA7AA52644B26AED8475C29143FC7chemguse_-- From owner-chemistry@ccl.net Mon Jan 8 17:10:00 2024 From: "David Shobe shobedavid|gmail.com" To: CCL Subject: CCL: wavefunction instability Message-Id: <-55079-240108165628-8072-2vGP9xSDdykErxznrQ88Lw]^[server.ccl.net> X-Original-From: David Shobe Content-Type: multipart/alternative; boundary="000000000000a706d9060e764436" Date: Mon, 8 Jan 2024 15:56:08 -0600 MIME-Version: 1.0 Sent to CCL by: David Shobe [shobedavid..gmail.com] --000000000000a706d9060e764436 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Typically the molecules are linear. Many are diatomic; others are carbyne-like linear wires, sometimes damn the imaginary frequencies, that try to turn into nonlinear clusters. (I'm not sure how interesting the latter are to the scientific public, but never mind that). The stated symmetries are "?", so no information there. On Mon, Jan 8, 2024, 3:33 PM T. Daniel Crawford crawdad- -vt.edu < owner-chemistry]=[ccl.net> wrote: > Does your system have any point group symmetry, and, if so, does the wave > function stability analysis categorize the instabilities by irrep? If so= , > then you can only follow the instability if you break the relevant > symmetry. Otherwise you'll always converge to the totally symmetric > solution. > > -Daniel > -- > Prof. T. Daniel Crawford > crawdad^_^vt.edu > > > On Mon, Jan 8, 2024 at 1:18=E2=80=AFPM David Shobe shobedavid .. gmail.co= m < > owner-chemistry^_^ccl.net> wrote: > >> This happens to me often. I have a calculation, but after checking >> wavefunction stability, it turns out to be unstable. So I use >> guess=3D(read,alter) or its equivalent to manipulate the orbitals, and r= un >> the calculation again. Only I get the same result: same energy, same >> instability. >> >> What is going on and what should I do in this circumstance? >> >> Regards, >> --David Shobe >> >> --000000000000a706d9060e764436 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Typically the molecules are linear. Many are diatomi= c; others are carbyne-like=C2=A0linear wires, sometimes damn the imaginary = frequencies, that try to turn into nonlinear clusters. (I'm not sure ho= w interesting the latter are to the scientific public, but never mind that)= . The stated symmetries are "?", so no information there.=C2=A0

On M= on, Jan 8, 2024, 3:33 PM T. Daniel Crawford crawdad- -vt.edu <owner-chemis= try]=[ccl.net> wrote:

Does your system have any point group symmetry, and, if so, does t= he wave function stability analysis categorize the instabilities by irrep?= =C2=A0 If so, then you can only follow the instability if you break the rel= evant symmetry.=C2=A0 Otherwise you'll always converge to the totally s= ymmetric solution.

-Daniel
--
Prof. T. Daniel Crawford
crawdad^_^vt.edu

On Mon, Jan 8, 2024 at 1:18=E2=80=AFPM = David Shobe shobedavid .. gmail.com <owner-chemistry^_^ccl.net= > wrote:

This happens to me often. I have a calculation, but after chec= king wavefunction stability, it turns out to be unstable. So I use guess=3D= (read,alter) or its equivalent to manipulate the orbitals, and run the calc= ulation again. Only I get the same result: same energy, same instability.

What is going on and what should I do in this circumstanc= e?

Regards,

--David Shobe

--000000000000a706d9060e764436-- From owner-chemistry@ccl.net Mon Jan 8 17:45:00 2024 From: "David Shobe shobedavid .. gmail.com" To: CCL Subject: CCL: wavefunction instability Message-Id: <-55080-240108171411-18122-h6P+rXqnKPKWX/+o5pWWbA!A!server.ccl.net> X-Original-From: David Shobe Content-Type: multipart/alternative; boundary="000000000000e5954e060e7683a1" Date: Mon, 8 Jan 2024 16:13:49 -0600 MIME-Version: 1.0 Sent to CCL by: David Shobe [shobedavid/a\gmail.com] --000000000000e5954e060e7683a1 Content-Type: text/plain; charset="UTF-8" Some are triplet. These have an even number of electrons, but I thought they were calculated unrestricted by default. I will check. The singlets typically do have an RHF --> UHF instability, but that doesn't worry me, except when the calculation finds a lower energy singlet that also reverts to the original wave function. On Mon, Jan 8, 2024, 4:01 PM Cory Pye Cory.Pye]![smu.ca < owner-chemistry]-[ccl.net> wrote: > David, > Are you using an unrestricted wavefunction in all cases? For an even # of > electrons, it defaults to a restricted wavefunction if not explicitly > specified. For rhf wavefunction, it will complain about an rhf to uhf > instability. > Cory > > Get Outlook for Android > ------------------------------ > *From:* owner-chemistry+cory.pye==smu.ca/a\ccl.net >

> on behalf of David Shobe shobedavid .. > gmail.com > *Sent:* Monday, January 8, 2024 1:42:11 PM > *To:* Cory Pye > *Subject:* CCL: wavefunction instability > > This happens to me often. I have a calculation, but after checking > wavefunction stability, it turns out to be unstable. So I use > guess=(read,alter) or its equivalent to manipulate the orbitals, and run > the calculation again. Only I get the same result: same energy, same > instability. > > What is going on and what should I do in this circumstance? > > Regards, > --David Shobe > > --000000000000e5954e060e7683a1 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Some are triplet. These have an even number of elect= rons, but I thought they were calculated unrestricted by default. I will ch= eck. The singlets typically do have an RHF --> UHF instability, but that= doesn't worry me, except when the calculation finds a lower energy sin= glet that also reverts to the original wave function.

On Mon, Jan 8, 2024, 4:0= 1 PM Cory Pye Cory.Pye]![smu.ca <owner-chemistry]-[ccl.net> wrote:<= br>

David,

Are you using an unrestricted wavefunction in all cases? = For an even # of electrons, it defaults to a restricted=C2=A0wavefunc= tion if not explicitly specified. For rhf wavefunction, it will complain ab= out an rhf to uhf instability.

Cory

G= et Outlook for Android

From: = owner-chemistry+cory.pye=3D=3Dsmu.ca/a\ccl.net <owner-chemistry+cor= y.pye=3D=3Dsmu.ca/a\ccl.net> on behalf of David Shobe shobedavid .. = gmail.com= <owner-chemistry/a\ccl.net>
Sent: Monday, January 8, 2024 1:42:11 PM
To: Cory Pye <Cory.Pye/a\smu.ca>
Subject: CCL: wavefunction instability
=C2=A0

This happens to me often. I have a calculation, but after = checking wavefunction stability, it turns out to be unstable. So I use gues= s=3D(read,alter) or its equivalent to manipulate the orbitals, and run the = calculation again. Only I get the same result: same energy, same instability.

What is going on and what should I do in this circumstance?

Regards,

--David Shobe

--000000000000e5954e060e7683a1--