Frequency calculation

Questions
#1

Hi
I am doing frequency calculation using the SF-TDDFT method using RSH functional (wB97XD), and it is taking 8-10 days to complete the job using 16 GB memory and 32 CPUs.
I want to know if there will be any effect of the memory on the speed like if I increase the memory then the speed will be increased?
coordinates:

$molecule
0 3
  N         7.3466180061    4.4824338068   28.5424492874
  C         8.6416036324    4.9766942362   28.5722854219
  C         9.6111588693    4.6022722708   27.5444467972
  C         8.7156295678    6.3486330284   29.1224367396
  C         7.5937890720    7.1768025803   28.9009627858
  H         6.6521164326    6.7128197190   28.6153117363
  C         7.7030618611    8.5597526403   28.9085700799
  H         6.8297564667    9.1737136343   28.6839425722
  C         8.9390156491    9.1611527492   29.1196233530
  H         9.0424433490   10.2461692141   29.0829280613
  C        10.0523533112    8.3582181254   29.3503228616
  H        11.0303954619    8.8202120651   29.4828441745
  C         9.9399395384    6.9753587952   29.3640780089
  H        10.8172140792    6.3477440278   29.4862680345
  C         9.8618473657    5.7952533552   26.7001346143
  C         8.7925797160    6.4659259085   26.0828875176
  H         7.8112938172    5.9883719271   26.0544293481
  C         8.9053597255    7.7855480435   25.6655859687
  H         8.0129651887    8.2897350609   25.3033385171
  C        10.0975130131    8.4881821241   25.7842285514
  H        10.1712773136    9.5355581066   25.4909436779
  C        11.1905088124    7.8240452879   26.3317287151
  H        12.1330362289    8.3556732475   26.4816021680
  C        11.0814955053    6.5092520184   26.7600505707
  H        11.9337115688    6.0634571545   27.2696108943
  C        10.7635812049    3.9338185776   28.1393921529
  C        11.9000893794    3.5620178929   27.3933136547
  H        12.0332716496    4.0118889595   26.4143397645
  C        12.7507542875    2.5436889956   27.7997755888
  H        13.6000073158    2.2711810030   27.1716178437
  C        12.4950051326    1.8143770102   28.9595119999
  H        13.1389853986    0.9837441682   29.2466729584
  C        11.3752203223    2.1483370772   29.7158292972
  H        11.1176506819    1.5615771582   30.5978632893
  C        10.5445276815    3.1904580310   29.3301166154
  H         9.6392110930    3.3619684730   29.9220667392
  C         7.2119356175    3.2620160970   27.8010218217
  C         7.7492125632    3.0446774745   26.5362759053
  H         7.9897136581    3.8456076057   25.8467644215
  C         8.0339136688    1.7273159830   26.2156740426
  H         8.6188369205    1.5535152879   25.3205594571
  C         7.6626218626    0.6486251664   27.0236151696
  H         7.9045993523   -0.3698830869   26.7201357532
  C         7.0228263557    0.8716616895   28.2300484533
  H         6.7612220485    0.0462421776   28.8907865722
  C         6.8745508644    2.1964840075   28.6347484848
  C         6.7831541028    2.7193473048   29.9782519267
  C         6.8648922122    2.0147792049   31.1757453240
  H         6.7528243600    0.9319556323   31.1851755078
  C         7.2016636069    2.7126575678   32.3195043796
  H         7.3512977154    2.1792080581   33.2570445492
  C         7.3308574617    4.1008179386   32.2730282415
  H         7.5042325489    4.6653655134   33.1797760601
  C         7.2497332713    4.8157763204   31.0906966921
  H         7.4243403795    5.8861418938   31.1000885323
  C         7.0137102647    4.0956264749   29.9287003107
$end
#2

Could you post the full input file please?

#3

Here is the complete input:

$molecule
0 3
  N         7.3466180061    4.4824338068   28.5424492874
  C         8.6416036324    4.9766942362   28.5722854219
  C         9.6111588693    4.6022722708   27.5444467972
  C         8.7156295678    6.3486330284   29.1224367396
  C         7.5937890720    7.1768025803   28.9009627858
  H         6.6521164326    6.7128197190   28.6153117363
  C         7.7030618611    8.5597526403   28.9085700799
  H         6.8297564667    9.1737136343   28.6839425722
  C         8.9390156491    9.1611527492   29.1196233530
  H         9.0424433490   10.2461692141   29.0829280613
  C        10.0523533112    8.3582181254   29.3503228616
  H        11.0303954619    8.8202120651   29.4828441745
  C         9.9399395384    6.9753587952   29.3640780089
  H        10.8172140792    6.3477440278   29.4862680345
  C         9.8618473657    5.7952533552   26.7001346143
  C         8.7925797160    6.4659259085   26.0828875176
  H         7.8112938172    5.9883719271   26.0544293481
  C         8.9053597255    7.7855480435   25.6655859687
  H         8.0129651887    8.2897350609   25.3033385171
  C        10.0975130131    8.4881821241   25.7842285514
  H        10.1712773136    9.5355581066   25.4909436779
  C        11.1905088124    7.8240452879   26.3317287151
  H        12.1330362289    8.3556732475   26.4816021680
  C        11.0814955053    6.5092520184   26.7600505707
  H        11.9337115688    6.0634571545   27.2696108943
  C        10.7635812049    3.9338185776   28.1393921529
  C        11.9000893794    3.5620178929   27.3933136547
  H        12.0332716496    4.0118889595   26.4143397645
  C        12.7507542875    2.5436889956   27.7997755888
  H        13.6000073158    2.2711810030   27.1716178437
  C        12.4950051326    1.8143770102   28.9595119999
  H        13.1389853986    0.9837441682   29.2466729584
  C        11.3752203223    2.1483370772   29.7158292972
  H        11.1176506819    1.5615771582   30.5978632893
  C        10.5445276815    3.1904580310   29.3301166154
  H         9.6392110930    3.3619684730   29.9220667392
  C         7.2119356175    3.2620160970   27.8010218217
  C         7.7492125632    3.0446774745   26.5362759053
  H         7.9897136581    3.8456076057   25.8467644215
  C         8.0339136688    1.7273159830   26.2156740426
  H         8.6188369205    1.5535152879   25.3205594571
  C         7.6626218626    0.6486251664   27.0236151696
  H         7.9045993523   -0.3698830869   26.7201357532
  C         7.0228263557    0.8716616895   28.2300484533
  H         6.7612220485    0.0462421776   28.8907865722
  C         6.8745508644    2.1964840075   28.6347484848
  C         6.7831541028    2.7193473048   29.9782519267
  C         6.8648922122    2.0147792049   31.1757453240
  H         6.7528243600    0.9319556323   31.1851755078
  C         7.2016636069    2.7126575678   32.3195043796
  H         7.3512977154    2.1792080581   33.2570445492
  C         7.3308574617    4.1008179386   32.2730282415
  H         7.5042325489    4.6653655134   33.1797760601
  C         7.2497332713    4.8157763204   31.0906966921
  H         7.4243403795    5.8861418938   31.1000885323
  C         7.0137102647    4.0956264749   29.9287003107
$end

$rem
basis = cc-pVDZ
METHOD = wB97XD
jobtype = frequency
SCF_CONVERGENCE = 8
MAX_SCF_CYCLES = 700
MAX_CIS_CYCLES = 700
UNRESTRICTED = true
SPIN_FLIP = 1
CIS_N_ROOTS = 4
THRESH = 14
SYMMETRY_IGNORE = true
SYMMETRY = false
CIS_STATE_DERIVATIVE = 3
$end
#4

Can you clarify at what step you’re seeing the slowdown? Increasing the memory won’t harm, if you see significant slow downs. Also remember that the hessian is computed with the finite-difference approach here, which takes some time for a system of this size.

#5

The problem is simply that there are no analytic Hessians available for SF-TDDFT so Q-Chem is using finite-difference of analytic gradients, as Kaushik suggests. There’s no way to speed it up. You should consider whether you really need spin-flip for your particular application. In some of the questions you’ve asked in the past, it hasn’t been clear to me why this was required.