user1271772

general recent conversations

2025 Matter Modeling Stack Exchange M…

Open discussion for mattermodeling.stackexchange.com/election/2

user1271772

02:00

Tristan, Tyberius, Hemanth, wzkchem5, are any of you here to answer questions (especially Tristan since your nomination was posted within only about 2 hours before the comment period closed)? I was not able to ping any of you, so maybe you haven't been in the room recently, but if you see this then it would be nice if you could make yourself pingable here for discussions about your candidacy!

user1271772

Jul 9 14:38

Hello everyone!

Spectroscopy & Potentiology

For discussions about spectroscopy and potential energy surfaces

user1271772

Jul 19 04:48

24-28 cores, not necessarily 28.

user1271772

Jul 19 04:45

It looks like I tried this calculation in 2017 and it needed more than 10 TB of RAM (with 28 CPUs, based on the number used in neighboring output files in the same folder):
```
Spin case277 Alpha: 2 Beta: 3
Number of excitations: 53577777552
Spin case278 Alpha: 0 Beta: 5
Number of excitations: 204094422
Spin case279 Alpha: 1 Beta: 4
Number of excitations: 9113909874
Spin case280 Alpha: 2 Beta: 3
Number of excitations: 48546399312

user1271772

Jul 19 04:41

For benzene, this is what I used in at least one of my input files in November 2017:
```
# in Angstroms, Herzberg 1966
unit=angs
geom
C
H 1 rCH
C 1 rCC 2 A
H 3 rCH 1 A 2 D2
C 3 rCC 1 A 4 D1
H 5 rCH 3 A 4 D2
C 5 rCC 3 A 6 D1
H 7 rCH 5 A 6 D2
C 7 rCC 5 A 8 D1
H 9 rCH 7 A 8 D2
C 9 rCC 7 A 10 D1
H 11 rCH 9 A 10 D2

rCC=1.397
rCH=1.084
A=120
D1=180
D2=0
```

user1271772

Jul 19 04:03

user1271772

Jul 19 04:03

The literature referenced by Ogren is as follow:
> "The rich vibrational–rotational spectroscopy of this molecule has been thoroughly presented in several sources (2–7)"

user1271772

Jul 19 04:00

That is from "Using the Asymmetric Stretch Band of Atmospheric CO2Wto Obtain the C=O Bond Length" by Paul J. Ogren (2002) doi.org/10.1021/ed079p117

user1271772

Jul 19 03:59

user1271772

Jul 19 03:59

Another value that I've found in the literature for R(CO) in CO2 is:

user1271772

Jul 19 03:57

user1271772

Jul 19 03:56

user1271772

Jul 19 03:55

They wrote that they got the "Expt" value from Ref. 33, which is "Geometrical structure of cyclopropane as studied by gas electron diffraction and spectroscopic data" (1985) doi.org/10.1021/j100261a027, even though the title doesn't mention CO2, they did re-calculate the CO2 bond length in it:

user1271772

Jul 19 03:53

That came from Xinchuan Huang's paper "An Isotopic-Independent Highly Accurate Potential Energy Surface for CO2 Isotopologues and an Initial 12C16O2 Infrared Line List", J. Chem. Phys., 136, 124311 (2012): doi.org/10.1063/1.3697540

user1271772

Jul 19 03:52

user1271772

Jul 1 20:59

I'll keep the room open this time Martin!

HPQC: High-Performance & Quantum Comp…

user1271772

Jul 18 01:10

```
Spin case 60 Alpha: 3 Beta: 3
Number of excitations: 99316041
Spin case 61 Alpha: 3 Beta: 3
Number of excitations: 33107261
Spin case 62 Alpha: 2 Beta: 4
Number of excitations: 23355552
Spin case 63 Alpha: 3 Beta: 3
Number of excitations: 96395913
Spin case 64 Alpha: 2 Beta: 4
Number of excitations: 23358720
Spin case 65 Alpha: 3 Beta: 3
Number of excitations: 32125200
Spin case 66 Alpha: 3 Beta: 3

user1271772

Jul 18 01:10

nike/wobbie-project1/nike/GW/borane_ae

user1271772

Jul 18 01:04

```
Number of excitations: 111078000
Spin case237 Alpha: 1 Beta: 4
Number of excitations: 73974000
Spin case238 Alpha: 2 Beta: 3
Number of excitations: 238392000
Spin case239 Alpha: 2 Beta: 3
Number of excitations: 715302000
Spin case240 Alpha: 2 Beta: 3
Number of excitations: 52976000
Spin case241 Alpha: 0 Beta: 5
Number of excitations: 3210120
Spin case242 Alpha: 1 Beta: 4
Number of excitations: 148104000

user1271772

Jul 18 01:04

/nike/wobbie-project1/nike/formamide/rest2

user1271772

Jul 18 00:57

```
Total CCSDTQ energy [au]: -155.557430489542

Perturbative corrections are calculated...
======================================================================
Spin case 1 Alpha: 0 Beta: 5
Number of excitations: 1502894554
CPU time [min]: 24661.784 Wall time [min]: 7753.242
======================================================================
Spin case 2 Alpha: 1 Beta: 4
Number of excitations: 62597592610
410,2 Bot
```

user1271772

Jul 18 00:57

```
Spin case 1 Alpha: 0 Beta: 5
Number of excitations: 1502894554
Spin case 2 Alpha: 1 Beta: 4
Number of excitations: 62597592610
Spin case 3 Alpha: 2 Beta: 3
Number of excitations: 322402950625
Number of 5 -fold excitations: 773006875578

Memory requirements /Mbyte/:
Minimal Optimal
Real*8: 691829.0484 691829.0484
Integer: 312.1394
Total: 692141.1879 692141.1879
```

user1271772

Jul 18 00:57

mcrowley/buta_ctdFromBeluga

user1271772

Jul 18 00:55

```
Perturbative corrections are calculated...
======================================================================
Spin case 1 Alpha: 3 Beta: 2
Number of excitations: 46093678
CPU time [min]: 26054.230 Wall time [min]: 26066.334
======================================================================
Spin case 2 Alpha: 4 Beta: 1
Number of excitations: 7460115
CPU time [min]: 30742.497 Wall time [min]: 30755.446
======================================================================

user1271772

Jul 18 00:54