Script nist-scraper.py¶
usage: nist-scraper.py [-h] [-u] formula
Retrieves and prints a table of molecular constants from the NIST Chemistry Web Book [NISTRef]
To do so, it uses web scraping to navigate through several pages and parse the desired information
from the book web pages.
It does not provide a way to list the molecules yet, but will give an error if the molecule is not
found in the NIST web book.
Example:
print-nist.py OH
**Note** This script was designed to work with **diatomic molecules** and may not work with other
molecules.
**Warning** The source material online was known to contain mistakes (such as an underscore instead
of a minus signal to indicate a negative number). We have identified a few of these,
and build some workarounds. However, we recommend a close look at the information parsed
before use.
**Disclaimer** This script may stop working if the NIST people update the Chemistry Web Book.
References:
[NISTRef] http://webbook.nist.gov/chemistry/
positional arguments:
formula NIST formula
optional arguments:
-h, --help show this help message and exit
-u, --unicode Unicode output (default is to contain only ASCII characters)
(default: False)
This script belongs to package pyfant
Usage examples¶
Usage examples:
nist-scraper.py TiO
will print
*** titanium oxide ***
State T_e omega_e omega_ex_e omega_ey_e B_e alpha_e gamma_e D_e beta_e r_e Trans. nu_00 A
---------- ----------- --------- ------------ ------------ ------- --------- --------- -------- -------- ------- --------- -------- ---
D 31920.0 1040 D <-> X 31940
e 1Sigma+ a + 26598.1 845.2 4.2 0.4892 0.0023 4.7e-07 1.695 e <-> d R 24297.5
f 1Delta (a + 19132) 890 0.50221 6.4e-07 1.67292 f <-> a R 19068.9
c 1Phi a + 17890.2 909.6 4.19 0.523 0.00313 3.9e-07 1.6393 c <-> a R 17840.6
C 3Delta_r 19617.0 838.26 4.76 0.047 0.48989 0.00306 -3e-05 6.7e-07 1.69383 C <-> X R 19334
B 3Pi_r 16331.3 875 5 0.50617 6.86e-07 1.66636 B <-> X R 16066.7
b 1Pi a+11322.0_3 911.2 3.72 0.51337 0.00291 6.1e-07 1.65464 b <-> d R 9054.02
A 3Phi_r 14431.0 867.78 3.942 0.50739 0.00315 -1e-05 6.92e-07 2e-09 1.66436 A <-> X R 14163
E 3Pi 12025.0 924.2 5.1 E <-> X 11871
d 1Sigma+ a + 2215.6 1014.6 4.64 0.54922 0.00337 6e-07 1.59972
a 1Delta a 1009.3 3.93 0.5376 0.00298 5.9e-07 1.61692
X 3Delta_r 197.5 1009.02 4.498 -0.0107 0.53541 0.00301 -1.1e-05 6.03e-07 3e-09 1.62022
nist-scraper.py OH -u
will print the same output with unicode characters:
*** titanium oxide ***
State T_e omega_e omega_ex_e omega_ey_e B_e alpha_e gamma_e D_e beta_e r_e Trans. nu_00 A
---------- ----------- --------- ------------ ------------ ------- --------- --------- -------- -------- ------- -------- -------- ---
D 31920.0 1040 D ↔ X 31940
e ⁱSigma⁺ a + 26598.1 845.2 4.2 0.4892 0.0023 4.7e-07 1.695 e ↔ d R 24297.5
f ⁱDelta (a + 19132) 890 0.50221 6.4e-07 1.67292 f ↔ a R 19068.9
c ⁱPhi a + 17890.2 909.6 4.19 0.523 0.00313 3.9e-07 1.6393 c ↔ a R 17840.6
C ³Delta_r 19617.0 838.26 4.76 0.047 0.48989 0.00306 -3e-05 6.7e-07 1.69383 C ↔ X R 19334
B ³Pi_r 16331.3 875 5 0.50617 6.86e-07 1.66636 B ↔ X R 16066.7
b ⁱPi a+11322.0_3 911.2 3.72 0.51337 0.00291 6.1e-07 1.65464 b ↔ d R 9054.02
A ³Phi_r 14431.0 867.78 3.942 0.50739 0.00315 -1e-05 6.92e-07 2e-09 1.66436 A ↔ X R 14163
E ³Pi 12025.0 924.2 5.1 E ↔ X 11871
d ⁱSigma⁺ a + 2215.6 1014.6 4.64 0.54922 0.00337 6e-07 1.59972
a ⁱDelta a 1009.3 3.93 0.5376 0.00298 5.9e-07 1.61692
X ³Delta_r 197.5 1009.02 4.498 -0.0107 0.53541 0.00301 -1.1e-05 6.03e-07 3e-09 1.62022