Calculating oscillator strengths

From NWChem

Viewed 265 times, With a total of 2 Posts
Jump to: navigation, search

Just Got Here
Threads 2
Posts 3

When I try to calculate oscillator strengths using CC2, it prints out the oscillator strength for the first excited state, but not for the others. Does anyone know, how to get the oscillator strengths for the other excited states?

There are three very similar previous questions on this forum, but none of them have attracted a response.

Thanks for the help,

All the best,


Here's my input:

  TITLE "Egg without spinach."
MEMORY 2500 mb

O -0.21588246 0.16922727 0.78153341
H 0.74571464 0.21510024 0.82795358
H -0.47503217 0.82191249 1.44197301

H library cc-pVDZ
O library cc-pVDZ


FREEZE atomic
THRESH 1.0e-4
set tce:thresheom 1.0e-4
set tce:threshl 1.0e-3


And here's the relevant section of the output:

EOM-CCSD transition moments / hartree
X 0.0000000 Y 0.3691437 Z 0.0000000
Oscillator Strength 0.0268294

EOM-CCSD dipole moments / hartree & Debye
X 0.0000000 0.0000000
Y 0.0000000 0.0000000
Z 0.2477967 0.6298413
Total 0.2477967 0.6298413

Singles contributions
6a1 (alpha) --- 5b2 (alpha) -0.9513669003

Doubles contributions

Excited state root  2
Excitation energy / hartree = 0.872579877010030
/ eV = 23.744116662209223

Excited state root  3
Excitation energy / hartree = 1.153901938036031
/ eV = 31.399282696456101

Excited state root  4
Excitation energy / hartree = 1.268696577055734
/ eV = 34.523005088977740

Excited state root  5
Excitation energy / hartree = 1.416550171084003
/ eV = 38.546307800889565

Task  times  cpu:      737.0s     wall:      844.7s

P.S. I'm running NWChem 6.8.
Edited On 9:50:47 AM PDT - Wed, Jul 3rd 2019 by Jmk12

Forum Regular
Threads 59
Posts 283
Actually, the calculation gets stuck at
CCSD iterations
Iter Residuum Correlation Cpu Wall V2*C2
When HF is deleted and io ga is added, it still gets stuck.
QA test tce_c2_cc2 also gets stuck.

I arbitrarily choose QA tests tce_n2, tce_cr_eom_t_ch_rohf, tce_eomccsd_gradient, tce_eomsd_somsol1,tce_eomsd_eomsol2,tce_lr_ccsd_tq, tce_c20_triplet, tce_hyperpolar_ccsd_small, tce_helium_imaginary and tce_eaccsd_ozone to eaxamine whether TCE can still work on my computer without the recompilation of NWChem6.8, fortunately all being able to finish. Thus, perhaps there is a bug in cc2 of TCE.

QA test tce_c20_triplet has many warnings during ROHF iterations, diffferent from that in the test.
QA test tce_hyperpolar_ccsd_smallgets stuck when running paralelly.

The output of QA test tce_helium_imaginary is not provided, and I do not know the physical meaning of the calculation, also whether it is correct.

QA test tce_rohf_uccsd can pass, and when I modify it into ccsd(t), it also can pass.

I have reported these and put all the log files on Github.

By the way, in order to obtain osccilator strengths, one should do left-hand eom-ccsd, but it seems NWChem only can do right-hand iterations, whereas GAMESS has this capability.
Edited On 6:35:54 AM PDT - Fri, Aug 30th 2019 by Xiongyan21

Forum Vet
Threads 10
Posts 1632
Github issue with fix at

Forum >> NWChem's corner >> Running NWChem

Who's here now Members 0 Guests 1 Bots/Crawler 0

AWC's: 2.5.10 MediaWiki - Stand Alone Forum Extension
Forum theme style by: AWC